Fuzzy has it pretty much all down there.... but another thing to keep in mind is that Blizzard is making the line between roles for hybrid classes a lot thinner.
Right now I am running

Prot Pally = Tank
Fury Warrior = Melee dps/back up tank
Elemental Shaman = Main Heler/DPS
Balance Druid = Back Up Healer/DPS
Arcane Mage = DPS

With this I also can use the druid for a back up tank. Gives a lot of versatility to compensate for the more complicated setup.
While questing I use them as full dps and a tank, while instancing the shaman goes full healing.

I just got these to 60 last week and am working on trying to find my next team make up. (Gota make full use of my RAF :) )
I was thinking about doing the full druid make up. This will give me a simpler set up as far as control and macro's go will giving me a extremely versatile team.