My original username was crashings12, which is something I picked when I was about 13 or so, because my favorite band was Falling Up (for some strange reason) and they had an album called Crashings, which had 12 tracks on it. Voila! That was one of my basic usernames for several years.
Finally, the summer before last, my siblings, who had been playing Final Fantasy XI for months, finally convinced me to try it. I spent at least half a day on my username. I was studying Greek at the time, and I wanted something pretty, since my character was a Mithra (aka a catgirl) and it was a fantasy setting. So I went through all my vocabulary words, looking for something that sounded pretty. People, Greek is not a pretty language. Finally, I found it. Aletheia - truth! That sounded cool. So, after trying a couple different spellings (my first spelling, Alethia, was already taken - can you believe that?!) I created my Mithra thief named Aletheia.
Since the end of that summer, I have been extremely sporadic about playing FFXI, and finally gave it up altogether, but I liked that name so much I started using it as my default username. I even named my Windows account Aletheia, since I couldn't give it the same name as my computer. The spelling has grown on me too - Aletheia rather than Alethia. It's more accurate, and it looks cooler too. There's more symmetry. Or something.
Anyway, this is beside the point, but a while back I was at a church service and a family group of singers was singing. I am usually completely bored throughout this whole sort of thing, and this time was no different, except for when the father was introducing his family. I don't remember any of the other names, but his youngest daughter was named Aletheia. I thought that was pretty awesome. It gives me the courage to maybe name my kid that someday.
Oh, and P.S. It's ah-LAY-thi-ah, not ah-LEE-thi-a. ^^