While this thread is still active...
About a month back I was pretty interested in building my own PC. I'm generally a Mac guy, but I'd like to learn more about PCs. I had no real need to build a PC, but wanted to learn how to put one together, and learn the Windows OS.
I eventually put off the project until next summer, as two computers in one dorm room would be pointless, but would I be better off buying a pre-fab PC first just to learn the general layout and how to troubleshoot? Or is the best way to learn jumping in?
--To not threadjack, everything I've read leans toward building your own, nostaligic1. There are tons of how-to guides out there, and if you have any technical lingo, you should be able to get it down with friends to help...
Disclaimer: That's only what I've heard. I don't know if it's true. 
Good luck!