I have an 8600GTS and i really like it, i might upgrade when really high demanding games begin coming out, but stick a 8600GTS and 2gb SLI ram you will get some nice resolution

Ran the Demo, My Spec, 1024 RAM (800Mhz) E6300 Overcloacked, Nvidia 7600GS, windows XP, 160Gig Hard drive. Ran pretty smooth