There was a really cool fighting game for the original Playstation called Battle Arena Toshinden (well... I thought it was cool, a lot of critics didn't agree). My favourite character was Duke, but I knew that I would never be able to get away with that alias anywhere online because there's a million people with/wanting that name, and I REFUSE to have a username anywhere online or in video games which have numbers, hyphens, or underscores... So I just took the last word in the name of the game, (i.e. Toshinden, cause it was still a cool name) and hoped that the fact that it wasn't a hugely popular game would allow me to secure this name in most other places that I went.
Turns out, it worked, so I usually use it on forums and online video games. Too bad the name doesn't fit for PKMN Diamond, so I had to shorten it to Toshi, which is fine, cause that's what most forum-goers and online friends call me anyway.