when will we see the gf 8 series answer to the gf 7600gt???

GeForce 6 series was launched April 2004 then the 6600GT was launched Nov 2004.

GeForce 7 series was launched June/Aug 2005 then the 7600GT was launched March 2006.

My suspicion would be that we'd see the 8600GT during the Spring refresh - so March/April 2007.

I'd speculate that we'd see a further drop in everything, so something like

Core clock of 400MHz
Memory clock of 800MHz
64 shader units
Shader clock rate reduced to 1000MHz
Memory bus width dropped to 256bit.

Just idle speculation