Re: new computer
it's actually pretty good that you bought a PCI-e card, since that's where everthing is going. There are some very good boards for PCI-e there, I would look at Abit, Gigabyte, Asus, DFI and MSI. Those are pretty much the big boys. Personally, I love my Gigabyte GA-K8N Ultra-SLI. I don't want to sway your decision, but these are the manufacturers I would check out. Go to newegg.com and anandtech.com and check some reviews.
Athlon 64 3700+ San Diego s939 | eVGA nVidia 7800 GTX
Gigabyte GA-K8N Ultra-SLI 939| Seagate Baracuuda 250 GB SATA
WD 80 GB | ASUS Vento 3600 Case (Red)