Hmm... my favorite avatars.... Besides my own, I'd have to say that Meg's (Alicewave's) avatar has always made me laugh. I also like BWSmith's avatar as well.
About my avatar... That's Basil, my first ever leopard gecko. My mom got him and his sister (Zoe), for me while I lived in Puerto Rico as a coming-home gift. Unfortunately Basil and his sis passed away just over a year ago... I've got other leos now... but he'll always be special to me.... He was always so 'quirky' I like my photo because (as a camara buff), I really love B&W's and contrasting lights and shadows... Basil was the best model I ever had!
As for facial shots... that's cool for the people who do it... But I don't think any of my photos are good enough to be an avatar! LOL =)