Probably Final Fantasy 10. At that time I was working the graveyard shift at a hotel, and I was doing a lot of writing on my own trying to get published. I would come home every morning at seven a.m. and play for a couple of hours alone in the quiet apartment, thinking about my own stories, experiencing the story of the game.
Other than that, I would say, honestly, the game that sucked most of my time was probably the original X-Wing game, which really made me feel like I got to be an X-Wing pilot, which, you know—Star Wars geek! That was so much fun! In a lot of ways every space game since then has failed to live up to the sense that I got from that game.