Aliens vs. Predator
Amnescia: Dark Descent (started it but only played an hour)
Assassin's Creed
Batman: Arkham Asylum (bought on sale because it was supposed to showcase 3dvision well)
COD:MW2 (90 minutes played)
Chronicles of Riddick/Dark Athena
Cities in Motion (45 minutes - seemed good but buggy. May play in the future)
Counter Strike Condition Zero & Deleted Scenes (only bought this to get early access to the CS:Source Beta way back in the day)
Dead Space
Dead Space 2 (bought on sale, might play in future if bored)
Deux Ex: Human revolution (played for 20 minutes, controls are so horrendously bad I couldn't play it)
Dungeon Defenders (played for 30 minutes, didn't really like it)
Elder Scrolls IV: Oblivion (already owned it, bought on sale with Skyrim. Played for several hours here and there but never really got into it)
Empire: Total war (played for 2 hours, didn't like it at all)
Fallout: New Vegas (played for an hour, thought it wasn't as good as FO3)
Far Cry 2 (garbage game, money wasted)
Gratuitious Space Battles (played for 1 hour, couldn't figure out what strategy to use to win, no guides around, shelved for later if bored)
Greed Corp (looked cool, bought on sale)
L.A. Noire (2 hours, crappy console port couldn't get into it)
Legend of Grimlock (just bought it to support the developers, no real interest in ever playing it)
Mafia II (I think I got this for free with a video card or something)
Max Payne 1 & 2 (already beat the originals, dunno why I re-bought them on steam, guess it was free or on sale or something)
Metro 2033 (played 20 minutes- horrendous controls, couldn't play it)
Orcs Must Die (got good reviews, bought on sale)
SimCity 4 (only bought it to get the soundtrack again, I lost my original CD)
Team Fortress 2 (got it with Orange Box, never played it)
Vampire: The Masquerade (heard lots of good reviews about it, but graphics are kind of dated and its buggy)
Warhammer 40k, Dawn of War (bought on sale, might get around to playing eventually)
Witcher 1 & 2 (next on my list to play, looking forward to them)
World of Goo (heard good things about it, but its such a horrendously bad console port it doesn't even run right on my machine - no widescreen or high res support)