It comes down to how much you want to PvE or PvP. I have a 3 sham, 1 pal, 1 mage group. I levelled it that way questing and instancing and the ports were cool. I hardly ever needed water or a sheep though.



Now I am 70, I am PvPing mainly just because it's the least time intensive way to gear up pre WotLk. I have actually dropped the pally for one of my previous 70s who is a hunter. Works better having 5 dps in PvP and the hunter has a few handy tricks, although a SL warlock would be better IMO



With regard to the mage, If I had my time again I would go shammie instead now I'm 70. Mage disintegrates in PvP and I am generally pressing buttons too fast to use any of the mages special skills. The great thing about shammies when boxing is that they have so many great passive abilities. 10k armour vs 3s. Totems, heals. For the PvP bonuses, there is not really much of a disadvantage in PvE to justify going mage IMO.