Here is the raiding elemental spec that I'm running with right now. There's not really much that's up for change in it, the points in Eye of the Storm could be moved for something like the decreased shock cooldown, but there's not much else.
The play style is very simple too. Recast flame shock to keep it up all the time, try to refresh it right after it falls off, but if that would mean delaying a Lava Burst, recast it earlier. If there are multiple enemies and you have the mana, cast Chain Lightning when it's off cooldown, otherwise, spam Lightning Bolt.
There's only 1 type of mail caster gear out there, and you share it with Resto Shaman. This does mean that you won't find any mail caster drops with hit rating on them. So you'll have to get your hit rating from tier pieces, gems, enchants, and non-armor equipment. Crit is an important stat for Elemental Shaman, but only up to a certain point, I've found 33% to be a decent amount to have while raiding (buffs included).
Other than satisfying that and your hit cap, you're going to want haste and raw spellpower. Elemental Shaman scale very well with spellpower because our crit multiplier for spells is 2.5. Haste won't have very tangible benefits for a while, because your spell casting is based around casting Lava Burst whenever it is ready, so you'll find yourself waiting and not casting spells while the last .5 seconds or so tick off of Lava Burst. But, if you stack enough haste, you'll find that you can cast 5 Lightning Bolts in between Lava Burst, and that's when it will really start to pay off.
As far as mana regen goes, Elemental Shamans have it pretty easy because we get 12% (approximately 1/8th) of our Intellect as MP5. When you're undergeared, make sure and have enough MP5 to last a battle, but as you're gearing up, you'll be replacing MP5 with Intellect, so you don't have to worry about MP5, and let those itemization point go towards MORE SPELLPOWER!
I honestly don't know what else to say. I had so much to say about Enhancement, this feels like so little. Oh...wait, AHA!
More on playing
It's definitely worth noting that stunned creatures will not be moved by Thunderstorm. This is a good thing. If you decide to take Improved Fire Nova Totem, you can get 1 big burst of damage, stun them, Thunderstorm, drop Magma Totem, and then step back to do Chain Lightnings. I chose to Glyph away the knockback from Thunderstorm for more mana. So I run in and drop Magma Totem, Thunderstorm, and run back out.
Don't forget Elemental Mastery, it's one of the only cooldown abilities that increases DPS and saves you Mana. Note that the increased crit chance will give you more clearcasting procs.
Ok, I'm pretty sure that this is all that I have to say.