People reading comments recently will have noticed that this site now supports Gravatars. (Globally Recognized Avatars). These little pictures go beside any comments you leave, allowing you to express yourself a bit and others to identify you at a glance.
Getting one is free and easy and is done from the site linked here. Once you have one, it will appear beside all the comments left on this site using your email address, as well as on all other sites that have Gravatar support in place.
[Update: 5 May 2008] I am trying out Identicons as a default image for those without Gravatars. They are automatically generated based on IP address and may make conversations with many commenters easier to follow.