[s]i guess Multiboxers are just normal human beings, there is always a % that will use internet's anonymity to become complete asshats.
Try again, better luck next time.[/s]
Damn you edited your post?

I think the main thing about multiboxing (2, 3, 5, x) is the burst damage. The idea of having x times the burst and take down any mob before they even come close.
For this, Elem Shamies (NS+EM+SL) or mages (PoM+Pyro) are perfect examples. Very high front loaded dmg.
i think locks/hunters would probably do well for that. Anything but melee classes i guess, since they require a much finer positioning which is not very easy with toons on follow.

It really boils down to what you enjoy playing, but remember that shamies are very weak in the early levels,and grow exponentialy after 40 :-)
good luck