Vegas 2 by far... COD4 is cool, but the fact you can custom outfit your player, the team work aspect, the co-op story mode, the terrorist hunts, etc makes Vegas 2 the best game to play online for me beating out COD4 and Halo 3 which used to be my favorite!
Madden 08 - 1000/1000
Cars Mater National - 1000/1000
TMNT - 1000/1000
Dead Rising - 960/1000 (Just Need 5, 7 Days)
Halo 3 - 900/1000
Scene It, LCA - 915/1000
And many more 1/2 way there!