Here's a breakdown of the 8000 series competition:
The new and improved GeForce 8800 GTS 640MB will have the same 500MHz core clock, 800MHz memory speed, and 320 bit memory bus as its predecessor, but it will supposedly feature 112 stream processors. That's 16 more than the current model, which boasts 96 SPs, but still 16 less than the full-blown GeForce 8800 GTX and Ultra, which both have 128 SPs.
Hmmmm, it would probably be worth the wait for the new GTS instead of getting the GT or the GTX.