I'm guessing that you have the single-core 3800+ processor. In that case, before upgrading the grahpics card(s), I'd upgrade to a dual-core CPU. I wouldn't upgrade the GPU now anyways, as DX10 cards are coming out in a couple months (hopefully by the end of this year). Two 7600GTs should provide enough performance for any game; just be happy with what you have.
I recently bought a 1gig RAM, SLI 7600GT's, and 3800+ AMD processor computer. Looking to upgrade as more things come out in time for Christmas, I asked another forum about my thought for a 7950GX2.
Oddly enough, they said a 4400+ was my best bet.
What do you guys say? I've about $300, and had planned to use the Graphic Cards as additional bargaining leverage, or selling for spare cash if I were to go out and get the 7950GX2.
Could a 3800+ even handle the GPU of a 7950GX2?