This is an excellent topic for a thread and I have been wondering about some of the avatars and user names until I found this thread.
My avatar is a picture of me when I was 10 years old. My abuse started at age 12, so I wanted a pic of me before my innocence was stolen, although my childhood was never happy. (Notice that I am not smiling.) I was going to use a pic of me when I was 11, but that is the age I turned into a geek, so I didn't want to use that.
BTW, I am not a geek anymore!
My user name is more of a wishful thinking name. I have survived undefeated thus far, but I still have doubts about if/how I will make it in the future, so it's an optimistic user name too.