6800gt is released in april 2004 so one of the first drivers should be good enough for the most part? Probably a later driver for the 2005 period?
Best advice i can give with this sort of stuff is to check reviews for cards AND games and see what software/hardware they used.
asus tx97-e, 233mmx, voodoo1, s3 virge ,sb16
asus p5a, k6-3+ @ 550mhz, voodoo2 12mb sli, gf2 gts, awe32
asus p3b-f, p3-700, voodoo3 3500TV agp, awe64
asus tusl2-c, p3-S 1,4ghz, voodoo5 5500, live!
asus a7n8x DL, barton cpu, 6800ultra, Voodoo3 pci, audigy1