Building 2011's Sub-$200 Computer
adeelarshad82 links to PC Magazine's recent account (updating a similar quest detailed last year) "to see if a decent PC could put together for less than $200. Turns out that between some great deals, an AMD processor, and a Linux OS, it can actually be done." They actually come out with a decent-enough system for that money — but omitting an optical drive in a full-size desktop computer build seems something like cheating.
I've got to say, at this point there's no contest as far as basic functionality goes, and for doing the things that "most people" tm do on their computers most of the time. Linux is clearly superior to Windows. I dare you to take a dual boot challenge.