Luskwood makes nice stuff, as does Lost Furest. There are a few others as well. I usually suggest the Northstar mall. On the Eastern most side is the avatar section, which should have quite a large selection.

I've been using my Luskwood avatar for a long time, myself, so give that a try. They're fairly easy to customize if you have the knack and want to try something simple to get used to customizing before you do anything advanced in the long run.