You're missing some of the best co-op games ever: Gears of War 2 and Resident Evil 5. Also, there are plenty of Xbox 360 XBLA games that have co-op. My favorite are Castle Crashers and Alien Hominid HD. If you still update the list, check http://en.wikipedia.org/wiki/List_of_cooperative_video_games and www.co-optimus.com for newer titles.