Here's the best PC mod EVAR: Compubeaver by Kasey McMahon, made from taxidermied beaver!
Link - Thanks Kasey! | If you haven't seen it, check out Neatorama's own Ultimate Case Mod List.
[Update 5/14/07: Kasey has written a step-by-step instruction on how to make your own Compubeaver in 29 easy steps!