31/0/5 is what I will be using before Cataclysm. Again, talents are easy to pick now and most of the optional stuff really is optional. Both the Drain Life and Shadow bolt approach are viable now, but Shadow Bolt really is more effective so if you wish to maximize your output, you should go in that direction.
Nothing to think about here, use Haunt, Lash of Pain and Bane of Agony as prime glyphs, Life Tap, Soul Swap and Shadow Bolt as major glyphs. Take whatever you like as minor glyphs. Obvious from the choice of glyphs, the Succubus will be our pet of choice now. If you decide to use Drain Life instead of Shadow Bolt or if you have more than 1400 haste, the Life Tap glyph is not needed.
The Chaotic Skyflare Diamond will be your meta of choice. As for others, try not to break socket colors and use a Veiled Dreadstone in blue sockets. Once you reach the hit cap, switch to pure +20 Intellect, as no socket bonus is worth 10 Intellect. As for yellow slots, use a Smooth or a Quick King's Amber if the bonus is more than 3 Spell Power, otherwise, just go for pure Intellect.
- Unstable Affliction
- Bane of Agony
- Drain Soul (If target is at less than 20% health)
- Shadow Bolt or Drain Life
- Shadow Bolt: Hit (17%) > Intellect > Haste > Spellpower > Mastery > Critical Rating
- Drain Life: Hit (17%) > Intellect > Mastery > Haste > Spellpower > Critical Rating
Reforge critical rating to hit and mastery as much as possible. Also remember that you will need 2 blue gems for your meta requirement, so you should make those +hit gems. Basically, fill your blue sockets with +hit/+int, then reforge your +crit to +hit until you reach the cap, then reforge crit to haste and if you can't reforge to haste, reforge to mastery.
- Unlike all your other dots, do not refresh your Bane of Agony while it's still on your target, because the damage it does ramps up nearing the end of it. Wait for it to run out and then recast it, or you will miss on some heavier ticks.
- Feel free to use Shadowflame if the situation allows it, as it's damage has been ramped up.
- Doomguard and Infernal have now become guardians and you can use them, on cooldown, beside your pet. Just consider them as damage cooldowns. The first one is for single target, while the second one is for AoE. Their strength is based on your stats at the moment of summoning, so try to chain up some trinkets or something before summoning them. Also, they will attack targets with the bane spell, so make sure you cast one before using them.
- Enchanting pretty much remained the same, as far as I can see so there are no new enchants to consider
All of this is purely theoretical. I cannot play the game at the moment, due to hardware issues so I'm just following logic, based on the info I have outside the game. If you feel I am mistaken about something, please let me know and I will check and correct it if needed.