Mine is from the movie "Metropolis," but it's really just a placeholder. I used to have a different avatar, which I've had some variation of since 2003:
I got the original version from a guy whose claim to fame was making "Anti-Dark" versions of the images you gave him (Areo Crunch, if any of you remember him); the basis for my avatar was my BBC #10 entry, but it's impossible to really see in there. I still don't know which parts are which.
Around 2008, I stuck it in the circular loading screen from the MNOLG and added a little sparkly .gif action, and believe me, I was looking wicked-rad. Unfortunately, it doesn't look good on the new boards because avatars have these little borders around them now. So admins, get on that, I suppose. No more oppression under the cruel borders of our avatars!