I wonder about a lot of other people's.. maybe we should start a whole thread under friends?
Anyway, back in the day (five years ago) when I was a child (15) I had a sort of obsession with coming up with weird screen names. I could list some off for you.. basicially it was inanimate objects (like a brown crayon, my black stapler) or two words being slapped together that usually weren't, like Psychotic Oysters (which is why my ebay name is lucid_clams).
I switched to more topic-appropriate ones earlier this year (KetchupPony for MLP, PirateParakeet for bird forums).. but basically I had to get back to what I was used to. It's just "old school" and natural for me.
Besides, my AIM name is ABC also. Easy to find me if anyone needs me.
Sorry that was so long-winded =)