Halo 3, Hitman: Blood Money, King Kong, Madden 06, NBA Live 06, NBA 2k6, Oblivion, DW5: Empires, and Tenchu Z.
I feel dirty admitting Madden and Live cuz those were just for boosting my gamerscore. There are lots of games I am close to 1000 too (specifically NB A 2k7, Saints Row and Perfect Dark Zero) but some of their damnable multiplayer achievements are almost impossible to get at this point in time. Then there was Civil War where I didn't bother to get the rest due to the stupid way they count "kills" in the game.