My main is a 5/21/35 Hunter, and I will say the best 1v1 class in the game , would be a frost mage, they got so many panic buttons against every class. A very good frost mage  can take any other class.

I also say MS warriors are very good. But warriors are so gear dependant, that without as many epics as the opponent, it can be hard to take them down.

When i play ab/wsg i always runs away from the warriors because i know i cant beat them ;).

Not even the best frost mage could beat a sl/sl lock who is decent.

Yah its mages hands down. Hunters pawn druids, warriors can't heal and are all melee, rogues don't have the armor and once you break their stun lock they're dead ... mages are vicious in 1v1.