Yes, I always use an avatar, and I use the same one almost always, I like to use an avatar that people identify with my username, so they know who I am and who they are talking to.
When I use forums, I like to be able to use an avatar that expresses me such as my Chibi that I use for my branding for my video game content creation. I also like to be able to see others avatars as well and I feel it brightens up the forum having avatars.
I haven't used a forum with no avatars in a very long time. I like them - it's nice to associate particular communication with a photo, because it mimics real life where we associate words with the face that speaks them.