I was surprised that the possibly greatest RPG-franchise of all time in console-gaming didnt have a thread of its own already. Time to change that 
THE HISTORY
The Final Fantasy series was created in 1987 by Hironobu Sakaguchi, who initially named the game "Final Fantasy" since he thought the game wouldnt be successful anyway and would be his last game. However the game was pretty successful and soon FF II and III followed in 1988 and 1990 respectively. Sakaguchi and his company Squaresoft started to gain recognition outside of Japan as well and for the new console generation in the early 90s, they released the next FF games for the first time not just in Japan but North America as well - the first of those being Final Fantasy IV in 1991, which became a milestone in RPG history and was the first game in the series that is considered a masterpiece. It was followed in 1992 by Final Fantasy V (which was also the last FF game directed by Sakaguchi) before they released Final Fantasy VI in 1994.
FF VI was the international breakthrough and is widely considered one of the greatest games ever made - it also remains the most highly-rated FF game in the series (Critics Score: 97 %) and was the final (main) game in the series on a Nintendo console and is seen as the end (and pinnacle) of the 2D sprites era. It was the first FF game with a highly praised storyline and multi-layered characters which was considered to be cinematic in scope. Until this day it is one of the most beloved RPGs of all time, with many old school fans of the series naming it as their favorite FF.
For the new generation of gaming, Squaresoft left Nintendo and moved the series to the new Sony Playstation, releasing the next games for the first time not only in Japan and North America, but in Europe as well.
The first game in this new generation was Final Fantasy VII, released in 1997. It became the biggest and most groundbreaking game of the entire RPG-genre and a record-breaking milestone. It has been called "the Beatles of RPGs" and rightfully so. FF VII was the first game which had CG movie scenes, polygon characters, 3D animations and pre-rendered CG backgrounds (which would become a staple of the series afterwards) and especially the characters and storyline were incredibly complex, dark and cinematic and unprecedented in its time, creating an almost movie-esque feeling. FF VII was also the first game in the series that took place in a modern setting instead of the traditional fairy tale setting of previous FFs. FF VII broke multiple sales records and went on to sale over 10 million units (making it still the highest selling game in the series until this day). It made Final Fantasy an international Mega-Franchise and Squaresoft one of the most successful game developers of all time. The enormous popularity and success of FF VII later led to several spin-off games (Crisis Core, Before the Crisis, Dirge of Cerberus) as well as a CG-film sequel (Advent Children), forming the "Compilation of Final Fantasy VII" which greatly enhanced and expanded the FF VII universe.
It was followed by Final Fantasy VIII in 1999, which heavily improved upon FF VII´s graphics and animations and at its time was seen as a technological wonder. It sold over 8 million units, making it one of the most successful RPGs of all time. The first Playstation era of FF was then concluded with Final Fantasy IX in 2000, which was also the last game that series-creator Sakaguchi actively worked on (and that he called the most perfect representation of his original vision for Final Fantasy). FF IX can be considered a "blast from the past" since it deliberately presented a setting, tone and design which paid tribute to the NIntendo-era (FF I-VI) of the series, while utilizing the technological style of FF VII and VIII, even improving further on their graphics and animation. While FF IX didnt sell as well as VII and VIII (the fairy tale design was something that turned off some of the newer fans who hadnt played the series prior to FF VII), it received great critical acclaim and is widely considered as the greatest of the classic games in the series.
Squaresoft moved the series to Sonys new Playstation 2 for the new generation, which allowed them to do several things with the series that were not possible before. As a result of that, the next game Final Fantasy X which was released in 2001 became a groundbreaking milestone for the RPG-genre and the FF-series which greatly redefined the style of the franchise and RPGs in general much like FF VII had done in 1997. FF X began a more cinematic era for the series and was the first game to feature 3D graphics, voice acting, animated in-game cutscenes to tell the story and much more realistic animations and CG movie scenes. The game was very successful (selling more than 6 million units) and received great critical acclaim, especially for its technological advances and powerful storytelling. It is widely regarded as one of the best PS2-games of all time and along with FF VI and VII its probably the most beloved game of the entire series. FF X´s female protagonist was recently voted the most popular FF-character in Japan. The success and popularity of FF X led to a sequel (FF X-2) in 2003, which had never been done before. In December 2013 a HD Remaster version of both FF X and X-2 with completely remastered graphics and revamped interface, music and charactermodels was released for Playstation 3. In North America and Europe it will be released in March 2014. much like the original game, the HD remaster received great critical praise in Japan.
FF X was also the last game in the series that Series-Creator Sakaguchi was attached to. After Sakaguchis CG-movie "Final Fantasy: The Spirits within" bombed immensely and nearly bankrupted the entire company, Sakaguchi took responsibility and left Squaresoft. Square had to merge with rival Enix Games to avoid bankruptcy, leading to the founding of the new company Square Enix (or in short SE)
The first new main title in the series , produced by Square Enix was Final Fantasy XI, which was released in 2002. Unlike previous games, FF XI was actually an Online-RPG. While that decision met with heavy criticism, FF XI (which wasnt released on Playstation 2 outside of Japan) nontheless was a great success and created a large online-community for years.
It wasnt until 2006 that SE released their first offline-FF game in the main series, which was Final Fantasy XII. FF XII was the final game of the series for the PS2 (and also the last Sony-exclusive FF game), which also was the first game in the series where Series-Composer Nobuo Uematsu didnt compose the music. FF XII was a critical and commercial success (Selling over 5 Million Units) but drew some heavy criticism from Fans who complained about the unusually bland characters, political storyline, the music (which wasnt nearly as powerful as Uematsus music for previous games) and the heavily changed battle system. Nontheless a sequel was released in 2007 (Final Fantasy XII: Revenant Wings) but only for Nintendo DS (A complete 3D remake for Final Fantasy III was later also released for DS)
In December 2009, SE released the first FF game for the new HD generation of consoles which was Final Fantasy XIII. FF XIII was the first (offline) game in the series released on a Microsoft console as well, though it was released on Playstation 3 first. While the enormously impressive graphics, the voice acting, presentation and the new dynamic battle system were highly praised, the game drew heavy criticism for its linearity, lack of player freedom and simplified gameplay mechanics. Until this day there is probably no other game that has divided the Fans of Final Fantasy so much like FF XIII. The game was nontheless extremely successful (selling nearly 7 Million Units) and spawned two more sequels (Final Fantasy XIII-2 in 2012 and Lightning Returns in 2013), making it the first FF game which was expanded into a trilogy of games. FF XIII´s main character Claire "Lightning" Farron has become one of the most iconic RPG-characters of all time and especially in Japan she is incredibly popular (Having been voted the most popular female FF-character in 2012 and the 2nd most popular character in 2013)
In 2010, SE released the second Online-RPG in the series, Final Fantasy XIV. However the game was very unfinished and was universally panned by fans and critics alike and later described as the greatest disaster in the history of the series. Square Enix reacted with drastic consequences, firing the entire development staff and having a completely new staff heavily revamp and overhaul the game. It was re-released in 2013 under the name Final Fantasy XIV: A Realm Reborn in a highly revamped version. This new version was met with very positive reviews and became a commercial success as well with many calling it the best FF game by Square Enix yet.
Square Enix had also been working on an ambitious spin-off game known as Final Fantasy Versus XIII, a dark action-RPG which was announced in 2006. After many delays and several problems during development it was decided to turn Versus XIII into Final Fantasy XV and release it for next-gen consoles (PS4 and X-Box One) instead. This makes FF XV by far the FF game with the longest development time and also the most ambitious FF game ever made. The game is expected to be released in 2015.
THE GAMES
1987: Final Fantasy (NES, Japan only)
1988: Final Fantasy II (NES, Japan only)
1990: Final Fantasy III (NES, Japan only)
1991: Final Fantasy IV (SNES, not in Europe)
1992: Final Fantasy V (SNES, not in Europe)
1994: Final Fantasy VI (SNES, not in Europe)
1997: Final Fantasy VII (PSOne)
1999: Final Fantasy VIII (PSOne)
2000: Final Fantasy IX (PSOne)
2001: Final Fantasy X (PS2)
2002: Final Fantasy XI (PS2 in Japan only and PC)
2003: Final Fantasy X-2 (PS2)
2004: Crisis Core - Final Fantasy VII (PSP)
2006: Final Fantasy XII (PS2)
2007: Final Fantasy VII - Dirge of Cerberus (PS2)
Final Fantasy XII: Revenant Wings (NDS)
2009: Final Fantasy XIII (PS3)
2010: Final Fantasy XIV Original Version (PC)
2012: Final Fantasy XIII-2 (PS3 and 360)
2013: Lightning Returns: Final Fantasy XIII (PS3 and 360)
Final Fantasy XIV: A Realm Reborn (PS3 and PC)
Final Fantasy X/X-2 HD (PS3 and PS Vita)
2015: Final Fantasy XV (PS4 and XBO)
THE SUCCESS
What follows is a Top 5 List of the critically and commercially most successful Games in the series:
CRITICAL
1. Final Fantasy VI 97 %
2. Final Fantasy IX 94 %
3. Final Fantasy VII 92 %
4. Final Fantasy X 92 %
5. Final Fantasy XII 92 %
COMMERCIAL
1. Final Fantasy VII 10 Million
2. Final Fantasy VIII 8 Million
3. Final Fantasy X 6.7 Million
4. Final Fantasy XIII 6.6 Million
5. Final Fantasy IX 5 Million

THE HISTORY
The Final Fantasy series was created in 1987 by Hironobu Sakaguchi, who initially named the game "Final Fantasy" since he thought the game wouldnt be successful anyway and would be his last game. However the game was pretty successful and soon FF II and III followed in 1988 and 1990 respectively. Sakaguchi and his company Squaresoft started to gain recognition outside of Japan as well and for the new console generation in the early 90s, they released the next FF games for the first time not just in Japan but North America as well - the first of those being Final Fantasy IV in 1991, which became a milestone in RPG history and was the first game in the series that is considered a masterpiece. It was followed in 1992 by Final Fantasy V (which was also the last FF game directed by Sakaguchi) before they released Final Fantasy VI in 1994.
FF VI was the international breakthrough and is widely considered one of the greatest games ever made - it also remains the most highly-rated FF game in the series (Critics Score: 97 %) and was the final (main) game in the series on a Nintendo console and is seen as the end (and pinnacle) of the 2D sprites era. It was the first FF game with a highly praised storyline and multi-layered characters which was considered to be cinematic in scope. Until this day it is one of the most beloved RPGs of all time, with many old school fans of the series naming it as their favorite FF.
For the new generation of gaming, Squaresoft left Nintendo and moved the series to the new Sony Playstation, releasing the next games for the first time not only in Japan and North America, but in Europe as well.
The first game in this new generation was Final Fantasy VII, released in 1997. It became the biggest and most groundbreaking game of the entire RPG-genre and a record-breaking milestone. It has been called "the Beatles of RPGs" and rightfully so. FF VII was the first game which had CG movie scenes, polygon characters, 3D animations and pre-rendered CG backgrounds (which would become a staple of the series afterwards) and especially the characters and storyline were incredibly complex, dark and cinematic and unprecedented in its time, creating an almost movie-esque feeling. FF VII was also the first game in the series that took place in a modern setting instead of the traditional fairy tale setting of previous FFs. FF VII broke multiple sales records and went on to sale over 10 million units (making it still the highest selling game in the series until this day). It made Final Fantasy an international Mega-Franchise and Squaresoft one of the most successful game developers of all time. The enormous popularity and success of FF VII later led to several spin-off games (Crisis Core, Before the Crisis, Dirge of Cerberus) as well as a CG-film sequel (Advent Children), forming the "Compilation of Final Fantasy VII" which greatly enhanced and expanded the FF VII universe.
It was followed by Final Fantasy VIII in 1999, which heavily improved upon FF VII´s graphics and animations and at its time was seen as a technological wonder. It sold over 8 million units, making it one of the most successful RPGs of all time. The first Playstation era of FF was then concluded with Final Fantasy IX in 2000, which was also the last game that series-creator Sakaguchi actively worked on (and that he called the most perfect representation of his original vision for Final Fantasy). FF IX can be considered a "blast from the past" since it deliberately presented a setting, tone and design which paid tribute to the NIntendo-era (FF I-VI) of the series, while utilizing the technological style of FF VII and VIII, even improving further on their graphics and animation. While FF IX didnt sell as well as VII and VIII (the fairy tale design was something that turned off some of the newer fans who hadnt played the series prior to FF VII), it received great critical acclaim and is widely considered as the greatest of the classic games in the series.
Squaresoft moved the series to Sonys new Playstation 2 for the new generation, which allowed them to do several things with the series that were not possible before. As a result of that, the next game Final Fantasy X which was released in 2001 became a groundbreaking milestone for the RPG-genre and the FF-series which greatly redefined the style of the franchise and RPGs in general much like FF VII had done in 1997. FF X began a more cinematic era for the series and was the first game to feature 3D graphics, voice acting, animated in-game cutscenes to tell the story and much more realistic animations and CG movie scenes. The game was very successful (selling more than 6 million units) and received great critical acclaim, especially for its technological advances and powerful storytelling. It is widely regarded as one of the best PS2-games of all time and along with FF VI and VII its probably the most beloved game of the entire series. FF X´s female protagonist was recently voted the most popular FF-character in Japan. The success and popularity of FF X led to a sequel (FF X-2) in 2003, which had never been done before. In December 2013 a HD Remaster version of both FF X and X-2 with completely remastered graphics and revamped interface, music and charactermodels was released for Playstation 3. In North America and Europe it will be released in March 2014. much like the original game, the HD remaster received great critical praise in Japan.
FF X was also the last game in the series that Series-Creator Sakaguchi was attached to. After Sakaguchis CG-movie "Final Fantasy: The Spirits within" bombed immensely and nearly bankrupted the entire company, Sakaguchi took responsibility and left Squaresoft. Square had to merge with rival Enix Games to avoid bankruptcy, leading to the founding of the new company Square Enix (or in short SE)
The first new main title in the series , produced by Square Enix was Final Fantasy XI, which was released in 2002. Unlike previous games, FF XI was actually an Online-RPG. While that decision met with heavy criticism, FF XI (which wasnt released on Playstation 2 outside of Japan) nontheless was a great success and created a large online-community for years.
It wasnt until 2006 that SE released their first offline-FF game in the main series, which was Final Fantasy XII. FF XII was the final game of the series for the PS2 (and also the last Sony-exclusive FF game), which also was the first game in the series where Series-Composer Nobuo Uematsu didnt compose the music. FF XII was a critical and commercial success (Selling over 5 Million Units) but drew some heavy criticism from Fans who complained about the unusually bland characters, political storyline, the music (which wasnt nearly as powerful as Uematsus music for previous games) and the heavily changed battle system. Nontheless a sequel was released in 2007 (Final Fantasy XII: Revenant Wings) but only for Nintendo DS (A complete 3D remake for Final Fantasy III was later also released for DS)
In December 2009, SE released the first FF game for the new HD generation of consoles which was Final Fantasy XIII. FF XIII was the first (offline) game in the series released on a Microsoft console as well, though it was released on Playstation 3 first. While the enormously impressive graphics, the voice acting, presentation and the new dynamic battle system were highly praised, the game drew heavy criticism for its linearity, lack of player freedom and simplified gameplay mechanics. Until this day there is probably no other game that has divided the Fans of Final Fantasy so much like FF XIII. The game was nontheless extremely successful (selling nearly 7 Million Units) and spawned two more sequels (Final Fantasy XIII-2 in 2012 and Lightning Returns in 2013), making it the first FF game which was expanded into a trilogy of games. FF XIII´s main character Claire "Lightning" Farron has become one of the most iconic RPG-characters of all time and especially in Japan she is incredibly popular (Having been voted the most popular female FF-character in 2012 and the 2nd most popular character in 2013)
In 2010, SE released the second Online-RPG in the series, Final Fantasy XIV. However the game was very unfinished and was universally panned by fans and critics alike and later described as the greatest disaster in the history of the series. Square Enix reacted with drastic consequences, firing the entire development staff and having a completely new staff heavily revamp and overhaul the game. It was re-released in 2013 under the name Final Fantasy XIV: A Realm Reborn in a highly revamped version. This new version was met with very positive reviews and became a commercial success as well with many calling it the best FF game by Square Enix yet.
Square Enix had also been working on an ambitious spin-off game known as Final Fantasy Versus XIII, a dark action-RPG which was announced in 2006. After many delays and several problems during development it was decided to turn Versus XIII into Final Fantasy XV and release it for next-gen consoles (PS4 and X-Box One) instead. This makes FF XV by far the FF game with the longest development time and also the most ambitious FF game ever made. The game is expected to be released in 2015.
THE GAMES
1987: Final Fantasy (NES, Japan only)
1988: Final Fantasy II (NES, Japan only)
1990: Final Fantasy III (NES, Japan only)
1991: Final Fantasy IV (SNES, not in Europe)
1992: Final Fantasy V (SNES, not in Europe)
1994: Final Fantasy VI (SNES, not in Europe)
1997: Final Fantasy VII (PSOne)
1999: Final Fantasy VIII (PSOne)
2000: Final Fantasy IX (PSOne)
2001: Final Fantasy X (PS2)
2002: Final Fantasy XI (PS2 in Japan only and PC)
2003: Final Fantasy X-2 (PS2)
2004: Crisis Core - Final Fantasy VII (PSP)
2006: Final Fantasy XII (PS2)
2007: Final Fantasy VII - Dirge of Cerberus (PS2)
Final Fantasy XII: Revenant Wings (NDS)
2009: Final Fantasy XIII (PS3)
2010: Final Fantasy XIV Original Version (PC)
2012: Final Fantasy XIII-2 (PS3 and 360)
2013: Lightning Returns: Final Fantasy XIII (PS3 and 360)
Final Fantasy XIV: A Realm Reborn (PS3 and PC)
Final Fantasy X/X-2 HD (PS3 and PS Vita)
2015: Final Fantasy XV (PS4 and XBO)
THE SUCCESS
What follows is a Top 5 List of the critically and commercially most successful Games in the series:
CRITICAL
1. Final Fantasy VI 97 %
2. Final Fantasy IX 94 %
3. Final Fantasy VII 92 %
4. Final Fantasy X 92 %
5. Final Fantasy XII 92 %
COMMERCIAL
1. Final Fantasy VII 10 Million
2. Final Fantasy VIII 8 Million
3. Final Fantasy X 6.7 Million
4. Final Fantasy XIII 6.6 Million
5. Final Fantasy IX 5 Million