In my opinion the 7900 GS is a killer video card. Excellent performance for the money. There are many motherboards out there compatible with AMD 64 x 2 socket AM2. Anandtech generally has good things to say about Epox. Stick with the major brands (ASUS, MSI, Gigabyte, Biostar) and you probably can't go wrong. The motherboard you have described is an SLI motherboard, which is only going to help you if you want to put in two of the same video cards. It will be less expensive without SLI. Depends on your budget. I think the AMD 64 X2 4200 with the 7900GS will play just about anything very well.
Concerning PSUs, I've always had good luck with the Enermax Noistaker II. I would go for the 420 watt or higher.
Cheers!
Concerning PSUs, I've always had good luck with the Enermax Noistaker II. I would go for the 420 watt or higher.
Cheers!