I would recommend you spend 1-2 hours reading the PvP forum posts and scanning threads about compositions that might interest you. That will get you far more input/education than your very open-ended post.

If you do not have much end-game multiboxing experience, I recommend a simpler team as your first PvP team. 4xShamans is a good start. Personally, I would not roll 5 of them, since it takes up a critical extra character slot in 10v10 BGs.