What spec for a warlock BG levelling with shaman.

I've got a spare slot in my shaman team and I figure I might take this opportunity to level my warlock with them.

I'm wondering which spec to use that would complement the shaman.

I'm leaning towards demonology, for soullink, felguard and demon form. Very simple spells.

I've discounted affliction due to it taking time to kill, which doesn't seem very synergistic with the shamans nuke it quick style (plus I've always viewed it as a very mobile style of play - drive by dotting). Of course the instant howl of terror would be nice.

I' m just not sure about destruction. I've never had too much success with destruction in the past, but it's been a very long time since i've played the lock and destruction has changed so much I'm not sure if it would be much better now.

Does anyone have any experience mixing warlocks with shaman for pvp?
Anyone with more recent experience with warlocks give advice on destructions viability?

Destruction does have a lot of nukes...plus the AOE stun (forget the spell name now) could come in pretty handy for dual boxing. I'm thinking do the stun...then several chain lightnings at once along with a rain of fire....could be pretty nice.

However, demonoloy is pretty good for the felguard...he does do a lot of damage and when he crits, he'll increase the spell damage of the group for a time. Mine crits very frequently. Demon form is a good one too for the increase armour and immolation aura if people start getting a bit close + the 20% spell damage buff is also nice.

I probably haven't helped here.

actually you have. :)

I'm going to go with demonology. I wasn't even looking at it from the buffs that it might bring.
I think if i went destruction I'd probably have the warlock as my lead to use it effectively.
The felguard does a nice chunk of melee damage too (almost like having a 6th party member :) )

destruction I bet. if only for the aoe stun

The demon crit, giving spell power will not stack with Totem of Wrath.
If your warlock is at 2800 spell power, these buffs are equal.
Under 2800, and the Totem is better; over 2800 and the warlock buff is better.

If you're going Demon, don't waste your points on those five talents.
Take your pick...
Either spend the 5 pts elsewhere in the tree making your demon stronger.
Or forgo Metamorphosis and those 5 pts, going deeper in Affliction or Destruction.

Affliction will get you... an instant cast fear.
You'll probably go with the Felhound for spell lock and decurses.
You'll go with a castsequence reset=target, which includes UA, Agony or CoElements, Corruption, Haunt, Immolate.
People detest warlocks because they're killing soemthing else and suddenly see 4 or 5 dots on them.
Then they die.

Destruction will get you nukes, similar to the shammy style of play.
You'll have the AoE stun, which is a mouse target move so either the lock is the main screen or you'll need a decent mouse broadcasting option.
The imp will be the pet, for some Fire Resist, a damage shield and hit point boost.

Demonology gets you a sick pet.
The pet will charge (intercept stun).
Soul Link transfers some of the damage you take to the pet (although this is early enough that either other spec can grab this for pvp's).
You can go 50/21 or 51/20 (Demo then your second spec), either Affliction or Destruction.
With talents, either other tree is a valid choice for your dps.
You'll lack a bit of the talents to make spells better, but the demon will get a ton of raw spell power.
Your Seed of Corruption spell will be sick.
I raided T5/T6 level on a Demo/Dest warlock, had a blast.

I'd go afflction since you'll spend most of your time in AV. (perhaps buy dual spec? destro for the other bg's).

In AV, you can spend your entire time spamming seed of corruption for gaudy numbers. Until you're upper 70's I'm not sure you'll really have the punch with destro that you might want, and demo is a bit boring.