I'm glad we don't (thought it's not avatars that bug me, but those extensive 'signatures' with way too much gobbeldy-gook in 'em that really bug me), but if we did, what would yours be?
I have one I use other places, and I love love love. It's also the wallpaper for the outside screen on my cell phone (Grohl's on the inside).
<img src="http://www.sloanmusic.com/images/band/chris.jpg" alt=" - " />