well before i was going to buy one i did a search on google, i typed in things like 6800gt vs. and 6800 reviews. to see what would come up and i believe i saw a comparison between the the cards you are interested in.
i have the 6800gt now and from what i read its the best for the money because it can be safely overclocked to 6800ultra speeds, which i am gonna do when i get some better ram... hope that helps.
by the way if you were wondering why nobody else answered your post its because your question is a common one and the answer can easly be found by searching..
but im just trying to get my post count up. he he
ASUS A8V Deluxe MOBO rev 2
AMD Athlon64 3500+ 90nm Winchester Core,OC'd @2.6ghz
PNY-Geforce 6800gt, OC@ 420/1.15
2x512MB Corsair Xms Xpert XL pc3200 2-2-2-5
2xWestern Digital Raptors 1-36.7G 1-74G 10,000 RPM HD/ 1x 160gb maxtor
Im water cooled now with swiftech mcw6002 and dangerden maze 4