I went Elemental all the way to 60 on my four shaman. Stuff dies so dang fast there's not much need for healing, maybe the occasional Lesser Healing Wave on themselves. Then I took one and ran her to 80, dual spec'd her for resto and elemental.

You can still throw up chain heals to a single key for each and should be sufficient healing in most non-instance related group quests and what not.

So, yeah, now I've got a group with a 60 Draenei Paladin, 3 60 Draenei Shaman and an 80 Draenei Shaman. Kinda gonna kill my XP for the 60s. And the whole 'phasing' thing in Northrend. Bleah. At least I hit 80 prior to doing half of Zul Drak, or any of Sholozar Basin, Storm Peaks and Icecrown.

Anyways, that's my take. I'm sure there are others who have done different... Especially since my butt was torn apart by some cow Enhancement shaman in AB last night... bleah.