I've always thought Alcibiades of Athenae had a good username. 2400 years old perhaps, but it has a nice ring to it and lends itself to a convenient abbreviation (AoA).
Other good usernames at CFC include Thunderfall, because it sounds awesome and powerful, Chieftess, which works well for the game especially now that she's a moderator, and Boundless, which is nice and optimistic.
Chieftess is now an admin.
To me, "AoA" will always mean "Award of Arms" which, in SCA terms means the recipient is entitled to display their own heraldic device and be addressed as "Lord" or "Lady." So in formal SCA situations, I'm entitled to be referred to as "Lady Freydis." I've never used "Freydis" as a username, but I'm sure lots of SCA-folk probably use their persona names online.
I'll give you some points in this competition, because the time that you were on the Around the World in 80 Days voyage and had to convince the post office to let you pick up a package addressed to madviking was pretty hilarious. It would've been amusing with a fair amount of user names, but your username being madviking definitely made it better.
True story told to me by a friend in our Shire (in Red Deer): She had to send a package to someone in the Calgary SCA group, on the Greyhound. When he went to pick it up, the conversation went something like this:

Hi, I'm here to pick up a package for Bill Foster.

(checks) Sorry, there's nothing here for that name.

(thinks a moment;
maybe she's forgotten my mundane name) Is there anything addressed to "Mynford Vygghelm"?

(checks again) Um... no.

(mutters aloud) Ohmygod, no, she wouldn't have...
Sure enough, the package was there... addressed to his older persona's name: "Chang the Suitably Obnoxious!"
So be aware that your username (or SCA persona) may end up in the postal system or on some other delivery label, and choose wisely.
