Well for me, a real Windows killer would be MacOSX, but i dont have the money for a new Mac box.
I use windows for games, and Macormedia/Adobe things.
Linux (redhat for anything else)
freeBSd as a server (apache, mysql and mailserver).
Good thing there is so much choice :-)
btw, i dunno whos site this is, i just want to compliment him/(her?) on it.