I’m surprised more people don’t know about Tiger Direct, but in case you don’t, check it out. Really cheap computers and parts — mine was built with stuff Chris the Tech Sensei ordered from here. And if you have a kid going off to school, you can’t beat the laptop prices! (Also, cheap TVs.)
Referral
Most of their stuff is recons and leftovers of last year’s models, but their huge inventory of parts and occasional off-the-wall goodies is worth getting the catalog mailed to you if you’re into this kind of stuff. Also, they own the rights to the name Circuit City, which has been reborn as a web-only merchant and offers similar kinds of stuff.