The 6600GT beats the 9800XT and 5950 ultra hands down in most tests, and the 6600 gets about the same benchmarks. Both 6600's are quite a bit better than the 9800 pro, although I wish the GT were 256bit (and 256mb). They're probably saving that up for the ultra.
Bad idea of ATi, releasing the X700XT. NVidia have scope for improvement (with the ultra), but ATi don't. They could always introduce a X700XT-PE, but that would be ridiculous.
Well done Nvidia
fedz