I've really enjoyed reading this thread, and the stories behind so many people's usernames! I'm a bit late to the party, but here's mine...
I've had my username for nearly 20 years, possibly longer. Aurian is the main character in a series of fantasy novels by an author named Maggie Furey. When I was a shy teenager who was just starting grow and mature, a powerful flame-haired mage was the perfect online persona for me. To this day, I still really like the books and the username, as it's not normally taken on most forums etc.