F.E.A.R. 2 - Best FPS this Gen
Farcry 2 - has it's flaws but it's extremely fun to explore the world
Jade Empire - An interesting setting for an RPG, and a great combat system.
Civilization 4 (or just wait for Civ5) - still the king of turn-based strategy games

You'll get a lot for a few bucks out of these games :

The Witcher
Dragon Age : Origins

you can buy for, pretty nothing, L4D2 and MW2 this week end on steam

also, you should play STALKER if you like FPS

and you can also try Medieval/Empire total war if you like "large army RTS"

and Dawn of War2 if you like "action RTS"

what kind of genre you like.

Anno1404

Don't you mean COD4? I thought the MW2 deal is a few bucks off the DLC for pre-ordering it.

Yes, please get Medieval 2 or Empire: Total War and taunt us all with how well it runs with your hardware. My 8800gt and e2160 are like the little train that could in those games because I like to play with the largest unit sizes.

oups,

yes, I meant MW1 which is CoD4

I just got : L4D2+CoD4 for 35 euros ... very good deal if you ask me.

Buy Left 4 Dead 2.

L4D1 + L4D2 bundle is $33 right now. There's a lot of content there for that price.

Assassin's Creed
Assassin's Creed II
Battlefield: Bad Company 2
Bioshock
Bioshock 2
Borderlands
Cryostasis: Sleep of Reason
Crysis
Crysis Warhead
Crysis 2
Dead Space
Dead Space 2
Diablo III

Dirt 2

Dragon Age: Origins
Drakensang: The Dark Eye
Elder Scrolls IV: Oblivion
Fallout 3
Fallout: New Vegas
Far Cry 2

Left 4 Dead
Left 4 Dead 2
Lost Planet: Extreme Condition
Lost Planet 2
Metal Gear Solid: Rising
Mirror's Edge
Modern Warfare
Modern Warfare 2
Prototype
Resident Evil 5
Singularity
Starcraft 2
Stalker: Call of Pripyat
World at War

Scratch the games that aren't even out, and you're set for now.

I really liked Dead space, played on ps3.. and also doom3 on pc :)

Now I am really happy playing fallout 3.