Three Hunters should do fine, but you might want to consider whether or not you feel you could do end-game effectively with three Hunters. If PvP is your only goal, you might be fine, but if you plan on raiding with them, it might be more difficult to get into a Guild.

With Priests, you may want a tank. I'd reccommend a Paladin based on other users' experiences, but a Warrior may do the job. I just mention Paladin since it gives you more wipe recovery and healing options with Shadow Priests.

What's the name of that one guy that's doing 5 Hunters? I cannot remember his name. >.<