Re: GeForce 6600GT Dual.
What was in there before? Dual 6600GT? They're pretty good. I would leave it if you don't want to spend any more money. I mean, it comes with those cards right? It will be a waste to get the 7800GT if the system you plan on getting already comes with dual 6600GT.
*Fact: Microsoft Window's Blue Screen of Death vs Computerforums.org's White Screen of Death. Which is worse?