My Avatars are normally of a Phoenix (to go with my name) or the Doomsday Clock or one of the 7 Superentendant Faces from Halo OSDT to go with my mood. My Fav is still my old Phoenix Avatar, like on my xfire profile.
Mine is a representation of what I'm going through or doing a lot of and at the moment it is writing. I change my avatar a lot, I get bored with the same old stuff and that goes for most things that I do in life. I have not finished a game in years, I start off playing it for days on end and then quit when I get close to the end, its a weird personality trait.