I picked up a refurbished original XBox specifically so i could install XBMC on it. Turns out it is a GREAT project, and through some trickery, was able to get it installed and running thanks to this post: http://www.boards.ie/vbulletin/showthread.php?t=2055256404 by 'SuperCell' at boards.ie. I highly recommend using this 'hotswap' method if you don't already have the gear necesarry to mod an xbox with a chip, or by using a savegame exploit. It'll save you some cash, plus who doesn't like yanking an IDE cable from a spinning hard drive?
Best of all, all of the tools used in the process run perfectly in WINE, or directly on my Linux desktop.