This guide is originally from /g/. It might be a couple of months old, but what this means is that the prices in the guide have fallen. Remember to search for the lowest prices for individual components, and go with retailers you trust. If you find a low price at a retailer you've never heard of / has bad ratings, see if you can get that component price matched with a more reputable retailer.
I got my last set of components at http://www.ncix.com/ , a Canadian retailer. I did my price comparisons at www.shopbot.ca. Your mileage may vary, of course.