I would recommend red orchestra 2 Heroes of stalingrad or Ostfront the original, its a realistic shooter that has a steep learning curve.
Red orchestra 2 is not out yet but will be available this September 13, The second one would probably better suit you because it has single player.
Edit...
I have bad stuttering on Gta 4 pc with my new rig, this doesn't make sense because now i have a better CPU and it stutters bad and i cant even play at high settings anymore. Any help would be greatly aprreciated. (btw i have a legal version)
With my old rig i was getting no stuttering and...
Another question, would i need any type of cooling i am not planning on 'oc' or will the 4850 fan be good enough?
Im planning on getting the XFX 4850 if that makes a difference and is the XFX a good choice?