Oh I have many.
Neo7 - My first used alies. Neo is my first name and 7 was my lucky number (initially used 7 because the name "Neo" was already taken on the first website I joined). Oldest username.
L - More of a gimmick than anything. Couple of users compared me to him and I liked his character the most in the Death Note anime. No longer used.
EnsignN7 - Considered to be my preferred "allies" in terms of games or email. Ensign is a Navy Officer rank and "N7" refers to Neo7. Originally it was just Ensign but had the same problem of it being used on other sites. 2nd oldest username.
Seta - Considered my actual nickname even though I think only two people use it. If people want to call me that then it's okay to. This is the most recent.
Life Sympathy - Rarely spotted username was going to replace EnsignN7 as my gamer allies. Didn't go through with it since few places allow the actual space (and I prefer the space opposed to an underscore or nothing at all).
Next one contains spoilers for Death Note:
Spoiler:Lawlite[L] - Lawliet is L's actual name (I've seen it as his last name in some sources with L being his actual first name which is clever to pretend it to be an allies for him). I made a typo in the name though (I also have the correct name "Lawliet[L]" ). This is my bot on the StarCraft channel that has ops privileges (moderator bot).
Desu[Shield] - This is a semi-spoof account for the Shield Clan that's used exclusively on StarCraft. I'm not in the Shield Clan (semi-pro Korean clan) though I like to pretend I am.
Suiseiseki - Gimmick/Fan account exclusive to StarCraft. Semi-regularly used.
Neo7[MBL] - Exclusively used in official clan matches in StarCraft (contains actual tag of the clan I do belong to). Not enforced and rarely if ever used.
Nuclear_Launch - My troll account on GameFAQs.
Motoko-Chan - This used to be my moderation bot on the StarCraft channel. No longer used.
have way more novelty accounts registered on StarCraft as well as spoofs though they are only for my amusement.
[Edited by moderator Neo7, 3/25/2010 9:12:06 AM]