I know its not what you want but I would start with prot pal and holy priest. (maybe disc for now untill you get 5-10 box)

Cause you will want more in the future ...

start with your core (tank/heal) and find others for dps. Then build on your core adding maybe mage (transportation) or ele shaman next.

Or maybe prot pal and the healing shaman spec. (then add priest later and move the shaman to ele)

Dont throw out your mages as at 5 I would go:

Prot Pal
Holy Priest (I think coh is better then renew but never used either)
Ele Shaman
Mage
Mage

I'v never play a druid so I don't know but I don't really see what they bring that this crowd dosnt. Also DK is good tank but just to much work, although death grip in pvp could turn the tide. Mage's let you strike a far range, something you cannot do with ele shaman.