Surprise. I've kept the same avatar for the last three years, with the exception of the following photoshops:
Prison Chimp
This was the first Photoshop that I can remember. I think I was stolen by another message board, so Cherry rescued me. This was a few months after I arrived here. Back then, everyone thought this was awesome photoshopping.
Yoda Chimp
This was the next photoshop that I remember doing in anticipation of the release of Episode I. The red X symbolizes the fact that I no longer have this image.
General Chimp
Ultimate Warrior Chimp
General Kael Chimp
These two are from the first Mock War and the miserable failure of Team Mock Wars. I got stuck with roonting in the team wars and he backstabbed me then disappeared.
I beat Carni, though, and he gave me permission to kick ass with his mask. Then everyone started using it.

I don't have that image anymore, either.

I was going to change my avatar to this about a year and a half ago, but Hobo said my current one was better.