I have two teams between 60-70, a pally/4shaman team and a pally/3mage/priest team.

My observations at this level:

The Pally/Mage/Priest team can kill anything, and kill it really fast. I've actually had the problem in a BC heroic of killing something too fast (the guy that summons elementals at 75%, 50% and 25%). I'd go from just fighting the guy to fighting the guy and 12 elementals, and I'd wipe. I actually had to slow down to kill him. While these guys kill really fast, they seem pretty squishy.

The Pally/Shaman team can also kill anything so far, but kills really slow. I leveled them enhance, and was able to clear all dungeons so far as enhance, except the dragon at the end of ramps. I left them spec'd enhance but used an elemental castsequence and got the dragon down.

So far I think I like the shaman team more. They have more passive buffs, and seem much more hardy and hard to kill. I don't have any idea how they'll do at 85.

Low level PVP is fun on both as well.