I've noticed that in some web browsers, a lot of user avatars were not displaying correctly (broken link) so the user had a 'red x' under their name like this:
I didn't notice before as firefox doesn't display them - but they show up in IE. This is an issue caused by when the database was rolled back - the URLs for the avatars were rolled back too, most probably to an image hosted somewhere on photobucket etc that no longer exists. I've gone through all of the affected user accounts and removed the broken links.
Hence, if you're missing your avatar, just re-add it by clicking on User CP > Edit Avatar, and upload one from there
Guess its just another little gremlim off the list!