Well, you know what Im going to say!
I think that all shaman should be part enhance, unless you are really willing to be on the fringe. Right now, its very difficult to be a fringe player in the 5mans, and possible 10-man content. Why do I speak such heracy(sp)? Because I like being able to do a little bit of everything. Resto shaman are great for instance healing, but horrible everywhere else. You'd have to ask Gwen about elem spec... Ive never gone fully down that road.
Crik, you and I have talked, but Ill say it again for the other shaman out there: It is perfectly possible to backup heal decently being elem/enhance with the proper gear. If yer willing to put forth the time and boost your +healing a bit, then you can still make a big difference. Also, that leaves you able to dps when yer out on your own, whether you carry a shield or not. Currently, Ive gone Enhance/Resto... Im giving serious thought to dropping Sham. Rage as its very inconsistent and NS might be more useful.
Right now, I see DW shamans as one of the premier DPS classes, and we can backup heal on bosses making us very useful. We boost our entire party. Sadly, with druids being nerfed we're going to have to be more careful, but we'll find a way.