Best Current MP guys
Tommynt (as always)
Alienware
Taz
Hitman
I've also seen a couple of NQ guys seem to be getting up there, but can't think of names at the moment.
Taz? Played this guy(edit: for the first time) into this game :
http://www.youtube.com/watch?v=A3-MP1lWx8c
But he got beat
Of course, with better coop they could stop anyone including me. NQ Pazuzu is a hell of a player too. I can also add NQ virus.