Allow me to say it again. The 6800GS is better than the 6800GT. You would be stupid to buy a GT. The GS will overclock to crazy high speeds, and beat the 6800 Ultra.
I believe I read earlier in this thread that he would not be overclocking it. The 6800GS is still a good choice even if you aren't overclocking though, because its still going strong even in today's games.
But the GT would be better stock. Idk how many times ive said already he wants stock out of the box performance so idk why anybody is bringing up the GS w/ OCing.
Since your on PCI-express, I'd say save $50 and buy the 6800GS. OCing is not hard at all, and even at a small OC, you can easily surpass 6800GT speeds.
This shows that the GT performs slightly better on high resolutions and with AA. But that doesn't include all games, if you look at COD2 you will see that the GS performs the same or better on all settings; and in FarCry they perform just about the same.
Now look at the overclocking with the GS. Thats a huge boost in performance from OCing, overclocking usually only give 3% increases on stock cooling from what I've seen and hear but this gives an extra 12 fps in 10 X 7 in Doom 3. He really should OC, but that is up to him.
Even without OCing it performs about the same and better in some cases for $40 dollars cheaper. The GS is the way to go.
I also had the decision between getting the 6800gs or x800xl both in agp. I chose the x800xl as more pipes are more important that clock speeds. My drivers are fine too!
My x800xl is great and im glad that i chose it over the GS.
Also i can play cod2 demo maxed out and i only have 512mb of ram.
If you really want a good agp card get the new 7800gs which is coming out very shortly.