Exapno Mapcase - if you don’t make up a name yourself, this is about as great as it gets.
SwimmingRiddles - cryptically poetic.
My favorites are the pun names like Sue Duhnym (not influenced by the fact she once said I was her hero (under my old name, zgystardst)) and Candid Gamera. But El Cid Viscoso is just plain brilliant, and as Google shows, utterly unique on the web.
Someone named runcible made one post in 2003. That’s pretty cool, too. “runcible spoon” would make a good user name.