Man. It's already been hard for people to choose a 640GTS or the GTX. Now nVidia created a middle man to complicate things even more.
I can already see people asking what card to get and ponder the 8800GT. Then there will be suggestions of "Go with the 640GTS, it's cheaper and almost the same performance." Or people will say something like, "Buy the 8800GTX, it's not too much more and you get better FPS."
Yay confusion!