The Resident Evil games are decent.
Then, Resident Evil 4 came out and just completely fucking blew my mind. I've played video games since Atari and have played a fair amount of them over time, but the Gamecube version of that game is by FAR my favorite game of all time. I got so good at part 4 that I actually played the entire game, start to finish, with 100% accuracy (using the 99 power magnum, granted, but still a geek accomplishment that I'm proud of). I played the hell out of that game and then traded it in. Once the new Nintendo system comes out, though, I'm going to buy it again, since it'll also play Gamecube stuff.
...for the record, 100% accuracy opens no new secrets of any kind, sadly.