I made a list for someone recently, so I'll just copy+paste:
PS3 Games
My FAVORITE next-gen series is the Uncharted series. Those games play like movies, and you get sucked in. 2 is the best. 3 just came out, so it's still pricey. 1 and 2 can be bought together for $29.99, I think, and that's going to be the best deal. 1 is good, but 2 is better. Do yourself a favor and play 1 first. Not really because you have to, but after playing 2, you won't like 1 as much.
Mass Effect 2. The first game is 360 only, and 3 comes out in March. I got 2 for $19.99, and I love it. It's kinda like Star Wars.
Dead Space and Dead Space 2. Scary as **** but fun.
Saints Row 3 (mine came with Saints Row 2 for free--not sure why). Totally inappropriate and ****ed up but VERY entertaining. I guess it's a little like GTA, but I've never played GTA.
Little Big Planet and LBP2. Very simple but very complex at the same time. It's best online, but I don't think online is required. The first one is better, but they're more or less the same thing.
Bioshock is great if you can tolerate FPS. I don't normally like FPS, but I love Bioshock for its story. Bioshock 2 is out, too. I don't like it as much and never finished it, but people like it.
Borderlands is also FPS. "FPS shooter+ RPG" Interesting game play but sucky story.
fighting games (not usually worth more than $30 because there's not much replay value...): Mortal Kombat and Marvel Versus Capcom 3. Tekken 6 is pretty cool, too.
Oh, and you might like Dragon Age: Origins. Must-have for RPG nerds... 2 is out, too. And Skyrim is a big RPG game. I haven't played it though.
That's all I can think of off the top of my head.
There was a major part of me that got it for Batman: Arkham Asylum and Batman: Arkham City too, though. They're pretty amazing and I recommend them. 
