I spent Christmas this year at my brother in-law's place. You may know my brother in-law as 'Ben White', or the guy who made the Kotaku redesign look all purrty. Anyway, Ben's just had a kid, he's married; he claimed he doesn't have any spare time to do anything. I almost believed him until I saw his Skyrim save file: 120 hours. It got me to thinking -- what games have you spent the most time with in terms of raw hours?
For me, it was Halo 2. Easily. Just in multiplayer alone, I estimate I put roughly 300 hour into that game. 300 hours. It really dominated my entire life for a while. I got diminishing returns from later Halo games, mostly because I never really found that deadly combination of boredom and spare time ever again.
Anyway -- what about you guys? What games have you spent the most time with?