The 8800GT is set to outperform the 8800GTS in all categories. I still wouldn't buy it. Right now I have a 6800XT and am looking to upgrade. I think anyone wanting to upgrade should wait a little while longer. First, around November 15, ATI is coming out with their new HD3800 series. These cards are based on 55nm versus Nvidia's 65. That means higher performance and less heat.
The ATI cards will most likely outperform the 8800 by a bit. Also, the 3800 will have D3D 10.1 support which the 8800 does not. Lastly, it will probably be pretty cheap for competitive reasons and due to AMD's financial troubles.
I am waiting untill November 15
