I don't like most avatars with animation, but the stick figure and the Do-the-Dew manage to pull it off without breaking up the page.
It's the avatars that flash a constant stream of disparate images that don't flow into each other that are really annoying. Or the ones with a flashy special effect or pulsating colors.
Argh argh. Vent vent.
But at least the forums aren't full of messages with giant image sigs like most gaming forums.