You forgot The Twitch. You know, the people with godlike reflexes who can and will pick up the sniper rifle of the game they play and headshot ANYTHING that gets in their way, usually with no scope, regardless of how erratically they or their target is moving.

And also The Man With The Identity Crisis: The guy who picks up a weapon for the sole purpose of using it the way it was NOT meant to be used. People who use sniper rifles for point-blank headshots, handguns for sniping (not referring to the Halo pistol mmk), anti-vehicle weapons for anti-infantry purposes, etc. Usually done for the sake of irony; the killer will usually find it funny that they managed to kill someone the way they did.

I like to fall into the latter category when playing Halo 3 and use detatched turrets for use in close-quarters combat, and magnums on pretty much anything, though my skill in said situations is very random. Sometimes I will wipe the floor with everyone and other times I'll die before firing the first shot.