This has been an interesting thread to read. I'll have to admit that I have never really thought about the various avatars other than finding it fun to see the various ones people choose.
Sometimes, I get confused when a person changes an avatar to look like someone else..then I have to check the poster's name to make sure because the post tone is different than what I have associated with that avatar.. (does that make sense?)
My long running avatars are usually just paintings that I want to own. Today, I changed mine to fit the season and the color I love.