I bought my last two motherboards, AGP graphic cards and memory from TigerDirect. They are really good about returns if you mess up and they are good about providing tech help online to be sure you get compatible components. Both of my motherboards are FIC and the graphic cards are Radeon. A good place to get memory besides TigerDirect is Crucial.com. I've bought a lot of memory there. They have a memory configurator to help you find the right type and they also have live online help at no charge.
Thank you Melinda. Now that you mention it, I remember Tiger from my "Computer Shopper" days (back when it was about as thick as a phonebook).