Making a little thread as the games I purchase increase.

Gears of War 3, (getting 1 & 2 soon)
Dead Island
Left 4 Dead
Dirt 3
Army of Two
Test Drive Unlimited 2
Call of Duty Black ops
Call of Duty Modern Warfare 2
Call of Duty Modern Warfare 3 (pre-ordered)
Forza 4 (pre-ordered)
Dragon Age
Borderlands
Split Second

I got the majority of these and some have co-op achievements so we'll have to do them at some point xD