I have a priest / 3 lock team at 63 atm, my priest is currently specced disc but doesnt have anything to do most of the time (questing atm). I instance boosted them to 60 w/ my prot pally so I dont have alot of expierience w/ the priest, I do have an 80 lock that I solo pvp w/ extensivly as afflic and I plan to run 4 locks and priiest for BGs and mabey fool around in the areana a bit. For lvling I think shadow priest would be best, I will probably respec or dual spec for instances w/ my pally when their 70+.