I have a simple AGP 5700le 256MB card. If you look on http://www.tomshardware.com the 6600 beats mine to dust.
In other words, I'd do that.
I'm trying to put together a relativley low cost comuter this is a first time project for my son and I. Would like to have semi good game play but have a limited budget. mb does have 1 pci 16x slot. Would a geforce 6600 card be good enough w/128 or 256 of ram or should we try to save up to get a geforce6800? any recomendations are greatly appriciated. Thanks