Rizzo's Transmet av makes me so happy.
I use this one on last.fm and a few other forums, along with "one percent" if I get vanity text.
My current is a close crop of a
photo I took of the National Cathedral in DC. I usually use a crop of the man and woman that are facing each other but wasn't sure if chiseled side-boob was appropriate. Later I caught sight of a penis-av or two so I may re-crop it at some point and go with the shot I like.
The tongue avatars freak me out though. I'm not really creeped out by split tongues, but like someone else said, maybe it's because it's repetitive.