For multiplayer:

Battlefield 1943
Fat Princess
Killzone 2
Resistance 2
Motorstorm: Pacific Rift
Ghostbusters
Resistance: Fall of Man
Little Big Planet
Damnation (ugh)
Battlefield: Bad Company
Demon's souls
Unreal Tournament III (mad cheap now)
Far Cry 2
Godfather II
Quantum of Solace
Motorstorm
GTA IV
Rag Doll Kung fu
Pixel Junk Monsters