whatever you do, use www.resellerratings.com
to read what people have experienced with online computer places.
I have used www.buy.com
tens of times without incident. I have also used www.mwave.com
and have not been able to beat their prices and service anywhere.
When you build, go for the Asus motherboard. I haven't heard one issue with them and peripheral stuff.
I had some trouble with my ABIT KT7A-RAID board and SB Live!, and ethernet card, and my HP printer.