Nate you're a kick in the pants dude.
Your system as is can play every game out there. I'd get a solid SSD for now, maybe get a 7970 as well. Call it good. Heck, if you really want to fork out even more money, pick up the PhenomII x6 1100T with a H100 and OC that beast. That is a formidable rig that'll TriviumNateHulkSmash any game out there.
Or, you could just send all that money to me.