either an AMD 6850 or 6870 will do the trick. If you want to go nvidia, a gtx460 or gtx560. I few months ago i retired my 8800gts. while the 6850 does provide a nice boost in performance, some games dont run well with only a dual core processor. Crysis will play at full detail 1080p no problems, just maybe not with AA turned on. Some newer games, like Crysis 2 and COD black ops, really need a quad core CPU to run smoothly along with a decent vid card.