My monk : Rogues, Shamans and Dks die easily.
My Lock : Mages, Priests, DKs.
My level 61 Priest : Everything other than warriors i can handle in 3s. OP at that level when your shield absorbs more than your health, your flash heal gets you 100% and your HOT heals for for 1/10 of your hp every second for 9 seconds. I once held mine against 5 players for 45 secs before they finally killed me.