You can play whatever classes and races you like. It depends on what you want.

Even 5 huntards will go well for you, or 5 priests. But you won't be able to pvp "well" with 5 huntards, and doing heroics is also a no no (as far as I know).

Personally, I would choose something along the lines of the holy trinity like mentioned prior. If possible use clases which will fare good in both PvE and PvP, this way you wont have to start over if you decide to do one thing or the other.