check out metro 2033, its been my favourite 360 game this year so far.

Mass Effect 1 and 2 and Fable II will keep you occupied for awhile!

castle crashers
dead rising
LFD2( i still much prefer nazi zombies but still a decent game)
mass effect series if your pc cant run it
bayonetta ( the better version on 360)

Trials HD
'Splosion Man
Forza 3
PGR 4
Shadow Complex
Viva Pinata

L4D2
Toy Soldiers
Gears 2
And Mass effect series but i have never played them myself.

LMFAO@someone mentionin Too Human

Mass Effect series
Halo Reach (in september)
Halo Wars
Gears of War series
Shadow Complex
Left 4 Dead series
Fable series (part three comes out in december)
Crackdown series (part two comes out later this year)
Kameo
Perfect Dark Zero
Lost Odyssey
Splinter Cell conviction (coming soon)
Alan Wake (coming soon)
Ninety-Nine Nights 2 (Coming Soon)
Kingdom Under fire 2 (Coming Soon)

Gears of war 1,2 ; lost odyssey ; L4D 1,2 ; tales of vesperia are must have games.

neverwinter nights 2???? who what where when?? if so ill be all over that i only played never winter nights 1 on pc and it still to this day in my top 5 favorite games ever , i heard 2 wasnt as good but its still within the same vein i love those rpgs so much!!!