I think Bioshock. The only problem with it is that it got far, far less artsy as the game progressed. I just beat it like 20 minutes ago, and last night I brought it to my friends house, started a new game on his Xbox, and played through the first level. I was in awe about how much I had missed and just ran through. It's beautiful, really. The shadows were draping over the majority of the level, you could tell the designers spent so much time on it (that's expected though since it's the opening). Later in the game everything seems to be either lit up, hard to see, or laid out right in front of you. I want a game to be explorable till the very end-I don't want to be able to expect what's going to happen or not be surprised at what I see.