I like the feeling of anomnyity created by NOT using your face in your avatar, makes you feel like you're able to get away with anything. Plus I made my Avatar here, it's based on a big drawing of the main character in a novel I've been writing for the past 10 years.
However, were I to use my face, I'd use this...
Of course I'd alter it a bit more in PS.
EDIT: Actually, do you guys think I should change my avatar to the above pic? I'd get rid of the text in the image and make it a more appropriate size first though.