I guess I should play this as well.
Back in the days of pre-Brood War Starcraft, I created a B.Net account. I actually used the name Dragon a lot at the time, so I tried it. Not knowing how naive I was that Dragon was quite a popular name, I tried searching it on the internet. I made a mistake, however, and typed in "Dragoon" instead and the very first link that popped up was
"Dragoon is already taken, but Dragoon1140 is available!"
So I used that on B.Net and it stuck ever since.