http://www.legitreviews.com/article/413/14/ - Benchies of 8800 at release
http://www.gamespot.com/features/6170621/p-3.html - recent benches
As you can see, performance can increase quite a bit with time, and in the older article Nvida said they had been developing 8800 for 5 years. Now its 6. It's exciting to see how much the R600 could improve, not that it's slacking.
As 650 comes out, It seems like it should be able to surpass the 8800 GTS fairly nicely, and maybe even become a competitor to the GTX. Even if not, if the performance should be between GTS and GTX, and so will the price, it should be a happy medium. I'm excited to see these benches- especially the folding ones.