Hello Spkid18,
Choosing a motherboard depends on many factors. I am a big fan of Newegg. It has a guided search which allows you to pick what you want the motherboard to be capable of supporting. So you can first choose an AMD board, then pick AM2 for the socket type, then PCI Express for video type, etc, etc, etc. If you are getting an Nvidia card, you should choose a board that has an Nforce chipset. Nforce chipsets are designed by Nvidia so they work very well with Nvidia cards.
A brand that I'm pretty sure everyone will agree is solid is ASUS, but I wouldn't choose to limit myself to a brand. Biostar is good, MSI, Abit. There are lots of good brands. I would just go by specs and price and just read reviews to make sure you aren't choosing some Wal-Mart brand.
Hope that helps. Post what you find and we can help you make sure you are getting a good deal
