Yahoo! Avatars is definitely something to be checked out, if only for its initial "oooh-there's-an-interesting-widget" value.
I did notice one really, really interesting thing. I'm not sure if Y! did this intentionally or not. When customizing your avatar, you get to pick a hairstyle. Y! Avatars offers you FOUR pages of hairstyles alone, so I decided to go through them all. And what do I see? The fourth (and last) page has only one hairstyle.
Yup, you guessed it - 'No hair'. Egghead!