Since it's a bit unfair to mix both the Live Action and CGI films together, I'm just gonna choose one from each series.
Live Action
Resident Evil: Retribution - While it's certainly over the top, I don't really mind. Anyone would be a fool to expect anything different from this series by now. I've already made peace with these movies being their own thing and I still find them fun to watch because that's all they really are, fun movies in a familiar universe. With that said, I found Retribution to be the most fun of all the films. It had Milla Jovovich in a sexy battlesuit, Sienna Guillory in a sexy battlesuit, awesome action, great visuals, payed homage to both the movies and games, and it had the biggest cast of video game characters of all the movies. Sure, they might have not done any of them justice, but they at least resembled the characters a lot closer than Chris and Claire. Also, sexy fight time between Alice and Jill!
CGI
Resident Evil: Damnation - While I enjoyed both movies, I give Damnation an edge because it was just all around more entertaining. The CGI looked amazing, the action was insane, and the tyrants were a cool nod to RE2, as were all the lickers. Plus, Leon has never looked better or kicked this much ass before. Just wish Chris was in it rather than that Buddy guy.