After toying around with the talent calculators for a few hours, I've come up with a ton of specs which all seem viable (especially in conjunction with the debuff limit increase). What are you considering post-expansion? Here are some sample builds that I've been considering... seems like a good time to bring my 'lock out of retirement. :)

Destruction

7/21/33 - I admit that this build isn't particularly synergistic, but DS gives it a number of viable playstyles: SB Spam, reasonable PvP longevity, or regeneration to fuel the mana-intensive Destruction tree while raiding. Like all the rest of the X/21/X builds, I can't find any better use for the filler points between the useful first tier and DS (apart from 3/3 Demonic Aegis). Fill these to your preference, I suppose.
7/10/44 - The logical extension of the 7/10/34 build, now with increased PvPwnage via Shadowfury. I included 5/5 Aftermath partially for raiding, given Blizzard's new fondness for the Dazed mechanic. Without Aftermath, Intensity and the Improved Searing Pain talent (especially with the PvP gloves) seem useful.
0/30/31 - This build sacrifices the utility in Affliction and deep Destruction for straight out DPS and more options via Master Demonologist.
20/0/41 - The typical glass cannon, extended 20/0/31. Improved Curse of Agony may be worth a look instead of Suppression, but I feel like one would be better off going deeper into Affliction, given the multitude of valuable talents following Shadow Mastery.

Demonology

20/41/0 - I doubt this build would be very useful for PvE, but given the insane survivability of 20/31/0 SL 'locks, I can't help but imagine running around with a Soul Linked Fel Guard. :ph34r:
30/31/0 - Unsure of this build's usefulness-- it really depends on how good Fel Guard really is. Nonetheless, the new Affliction tree has some downright amazing talents in it...
7/41/13 - Another PvP build I threw together.
0/40/21 - The new and improved MD/Ruin. I don't know how Shadow Bolt spam will compare with either Destruction (Conflag) or Affliction warlocks come the expansion, but this is probably the epitome of the SB strategy.

Affliction

41/9/11 - The Affliction tree is really the interesting part; I for one would love to see Dotlocks compete with nukers on the damage meters. I neglected to include Shadow Embrace, but it seems like a solid raiding talent. Given the deep investment in Affliction, I excluded Improved Life Tap in favor of Dark Pact, though given the current scaling Life Tap may be more useful.
40/21/0 - I'm really not convinced of Unstable Affliction's value, especially given how much DS and the Demonology Tree would add to the build.

In terms of specific talents, Shadow Embrace, Mana Feed, and Soul Leech really catch my eye. I've never played a non-caster, so I don't know the value of the first, but I figure it can't be bad. Mana Feed essentially guarantees that your pet will never run dry, but I doubt that the Imp would survive very long if allowed out of Phase Shift. Soul Leech seems like a better version of the Mage talent that refunds spell crits; I don't know the aggro numbers on Searing Pain (I've never used it in a raid) but SP spam would be a surefire way to proc a lot.

Anyway, the gist of my post is: how will you spec come the expansion?

I'm going to go with 9/5/47. I might drop Soul Leech if it ends up sucking, but I'm not sure what I'll replace it with. I don't see how you can call that 7/10/34 a PvP build without Intensity and Nether Protection. :(

7/43/11 or 0/21/40 are my top two choices. For the former, swap out two points from Mana Feed into 2/3 Fel Stamina if so desired. I'm really, really interested in the Fel Guard from both a PvP and Raiding perspective, though it's agonizing to not have an idea on how the Fel Guard performs in reality. If he sucks, then so be it.

For the latter, I was thinking of a heavy Immolate/Incinerate/Conflagrate build using an Imp Sac so I can work together with Fire Mages laying down imp Scorch. Problem with this build is that there's almost no utility in it.

7 / 13 / 41

I'd pick up 3/3 Demonic Aegis. It compliments Fel Armor which plays very nice with the new talent Soul Leech.

--

Soul Leech: Gives your Shadow Bolt, Shadowburn, Soul Fire, Incinerate, Searing Pain, and Conflagurate spells a 30% chance to return health equal to 10% of the damage caused.

Fel Armor: Surrounds the cast with fel energy, increasing the amount of health generated through spells and effects by 20% and increasing spell damage by up to 100. Only one type of Armor spell can be active on the Warlock at any time. Lasts 30 min.

Demonic Aegis: Increases the effectiveness of your Demon Armor and Fel Armor spells by 30%.

--

Demonic Aegis 3/3 would buff Fel Armor from 100 spellpower to 130. I get that.

How would the health return work when all three spells/talents are taken into consideration? Soul Leech is buffed by Fel Armor, which is buffed by Demonic Aegis. Anyone care to run some numbers for me and guess how that works?

:)

/confused

Anyway, and then in Destruction, I picked up the usual suspects down to a normal 21 pt. Ruin build and added:

5/5 Improved Immolate
3/3 Nether Protection
2/5 Emberstorm
Conflagurate
3/3 Soul Leech
5/5 Shadow and Flame
Shadowfury

http://forums.elitistjerks.com/viewtopic.php?id=8156
http://forums.elitistjerks.com/viewtopic.php?id=8107

C'mon, guys. Were these other two warlock threads not good enough to post this in?