The 8800 GTS/GTX requires the latest beta driver of nvidia. This driver is in portage, however for some reason it does not install the required libwfb library. I corrected this issue on my system by downloading and installing the driver from the website, but it took me awhile to figure this out as the details on this are sparse. Besides, either way the driver in portage needs to be fixed, at least for amd64, as this important library/xorg module is not installed.
Bump.
Bump, eh? How about a patch, instead?
I have has this problem with my 8800 GTX and could do with a patch.
Created attachment 103461 [details, diff] Patch to add wfb module to nvidia-drivers.
Fixed in CVS... thanks for the patch!