Now that’s actually a semi-interesting story. Back about 10 years ago I started a Star Trek fan fiction called “Star Trek: The Elite,” and in this story the main character was Captain Smith. His ship was the USS Valor.
Now, when it came time for me to pick a better handle than my first Internet name, I chose to make one from these elements. So I went by “CaptainSmithUSSValor” until I ran across a signup that required me to have a shorter username. At that point I shortened it to “CaptainValor” and it’s stayed that way ever since.
Incidentally, I uploaded the fanfic to Scribd if you’re interested: http://www.scribd.com/doc/29818054/Star-Trek-The-Elite