My story is fairly mundane - when confronted with the Unix B login request form, I had to come up with an account name. Having just come from High School, I'd played a lot of D&D, and the most recent major character I'd been using was named Shonnon, so I just picked that for want of anything better, and it's stuck.

orcus wand

Shonnon was a monk who had his eyes ruined in battle, but had magic glasses that let him see things others couldn't (and they thought they were being original with Geordi LaForge :-).

A mildly amusing story related to the login is that, at some point during my one and only year as a student, someone showed up with the login "shannon". I sent them email that went something like:

From: shonnon
To: shannon
Subject: this system ...
isn't big enough for the two of us. I'll meet you in /dev/null at midnight for a duel. rm -r at twenty paces.

I never got a reply, and they stopped logging in shortly thereafter. I guess they didn't realize I was kidding. :-)

My other login, keithr, was just the one that SCO assigned me. It tends to get pronounced "keither", which I like, so I've kept using it.