I like bright skins, with black on white text for messages, so that rules out several skins as a potential favorite, though they may be great eye candy.

I'd have to say my current favorite is Sylvester, with WinXP Silver a close second. WinXP Silver might be a little better artistically, but I love Sylvester's color scheme.

The Skins (Skinz) theme is also very cool, especially with the big turkey up there.