Rather arrogant post above imo, but being a well geared shaman across all 3 of my specs, shaman have a ridiculous amount of verstility, and I have a hard time staying 1 spec. For the pvp aspect it depends on your type of PVP. Arena wise Resto is a great choice, throw Earth Shield on yourself and you become amazingly durable. 5v5 situations as well as BG's elemental is great for devastating burst dps, assist off a warrior with WF totem dropped for them and you can down almost anything instantly. Enhance is great for killing casters but relies heavily on closing that gap and not ending out being kited to death as the frost shock snare isnt always enough to counter a freezing trap, blink, fear or most types of cc.
Pve if your a raider, my most successful specs are 41 0 20 being as an elemental, mana conservation is key for long fights and spell crit = mana efficiency and higher damage. And 16 45 0, in raids you really shouldn't have to heal yourself and the 16 pts into elemental will give you the talents to reduce shock cd by 1 seconds which Theorycrafters will quickly see as a huge dps improvement as long as you can keep your mana high.
Between the 2 I prefer elemental as it is a little easier to control threat and dps'ing from a distance I can keep an eye on things going on around me. Though most larger raids should definitely require and enhance due to the mass buffs they can give to melee as well as an elemental via Stormstrike.

Griska, yeah your type of comments r the ones that I was referring to, ty for proving my point that people can not post on forums like this without down playing someone else.  Someone has to always make a comment, no one can post their own opinions from experience without someone with a different view bashing them.  Nothing in my comment was meant to sound arrogant, it's experience from grinding as an enhancement shaman.  Everyone has different styles that is why there are 3 talent trees, it's the freedom of choice of how you would like to play your toon.  The subject of this one was whether to go Elemental or Enhancement?  The answer u see above is why I play Enhancement and not Elemental, so if u still pull arrogance out of the post I apologize for my rudeness