[EDITED: I revised my stance on some talents due to a few reasons -- I wrote this guide before 3.0.2 went up and I also let my PvP bias get in the way of some talents. Here's a PvE-oriented Affliction DPS build.]
Of all the trees, Affliction got the most love from the developers. It is, in my humble opinion, the most fun and dynamic tree right now, if somewhat complicated as full Affliction Warlocks will have to work in more spells into an already complicated cycle.
On the first tier we've got Improved Curse of Agony, which was pulled up from Tier 3 for the exact same points and effect. That's an incredibly good deal -- if you use Curse of Agony a lot. The truth is, the original version was too deep in the tree to begin with. If you mostly PvP, you can skip this talent since your staple curses are Tongues and Exhaustion. If you mostly raid, you can consider this a cheap DPS boost.
With the move away from resistance mechanics, Suppression was reworked to give 3% hit instead for three points as well as reduce the cost of Affliction spells by 6%. That's pretty darn good for a mere three points and is about the best talent in tier one. We should also celebrate the fact that instant Corruption was made baseline, merely one of the wonderful things to happen to Warlocks in Patch 3.0.2. Of course, this means Improved Corruption was reworked -- buffed, actually -- to grant 10% more damage to Corruption and 5% more crit to Seed of Corruption. I'd normally say max it out, but this is just the tip of the iceberg. Max this out. Pew pew.
Tier two is pretty much unchanged with the exception of Frailty, the renamed and reworked Improved Curse of Weakness. It now also removes the attack power bonus of Curse of Recklessness. It's still not a talent I'd take despite the buff, but can be useful for raids because the armor reduction of Curse of Recklessness stacks with Sunder or Expose Armor. Everything else on this tier is pretty much status quo, which means you should invest 2 points in Improved Life Tap.
On tier three we have the new talent Improved Fear, which takes the spot vacated by Improved Curse of Agony. The spell essentially makes Fear a snare effect, which is extremely handy for PvP since you'll be casting Fear a lot, anyway. It's not so hot for PvE, although it can be fun to juggle with Fear and Curse of Recklessness.
Fel Concentration was buffed to a three point talent, down from five, and now reduces the amount of pushback received. This is due to the change in pushback mechanics, which really should help us get that Fear off while some filthy Rogue is pummeling us with his stupid maces. This makes Fear castable within 1.8 seconds at its longest (versus 2.5 without the talent). Max it out for PvP, completely optional for PvE.
I know I said Affliction got lots of love, but there's something seriously mind-boggling about the new Amplify Curse, which now passively reduces the global cooldown of Curses by .5 seconds. 11-point talents are supposed to be definitive, but this is just definitively retarded. Conceptually, a reduction in GCD should be cause for celebration. But curses? I really hope this talent gets changed soon because right now, it's about the worst talent in the game. Unfortunately, it's required for Curse of Exhaustion, so you're just going to have to waste one point here. so save yourself two talent points and skip them both. You won't need Curse of Exhaustion for PvE.
There are virtually no changes to the fourth tier, merely a clearer wording on Empowered Corruption. For most DPS builds, this is a decent 3-point investment because Corruption is pretty much the one spell that's always on a target. The unchanged Grim Reach and Nightfall are pretty much standard investments, as well.
On the fifth tier, we get the deliciously reworked Shadow Embrace. Old hybrid builds picked up only one point here just to pad the debuffs, but it now also gimps heal-over-time effects on the target by 30%, sort of like a Mortal Strike for HoTs. Not only that, it also increases periodic damage dealt by up to 10%. The downside? It forces the use of Shadow Bolt and the 51-point talent Haunt, making it more difficult to apply. If you're going all the way up to Haunt, however, maxing this out is pretty much required. Sitting on the same tier is Siphon Life and Curse of Exhaustion, two of the best 1-point investments you can make and almost good enough to make up for the suck of Amplify Curse. Almost. But Amplify Curse sucks so bad it makes babies cry.
An unchanged Shadow Mastery sits on the sixth tier. It's still an awesome DPS boost, but now it has a friend sitting beside it -- the brand new Improved Felhunter. If you're committed to Affliction, the Felhunter is the pet for you, it's just that simple. Only fools will laugh at us for bringing out our puppies in a raid or 5-man because not only does it now bring a raidwide buff, it's also designed to deal DPS that scales with number of DoTs you have on the target. Sure, it's still squishy and can be one-shot by a boss, but it's a good start.
Getting overwhelmed? Don't, because we only just got started. Contagion on tier seven is the same old spell you've always picked up on the way to Unstable Affliction. If you're this deep, 5 points in Contagion is mandatory. Dark Pact was unchanged, too, buffed to a 200% return and is an awesome 1-point talent. In fact, you can now use Felhunters as a mana battery instead of the Imp, thanks to the mana replenishment provided by Improved Felhunter.
The same tier also sees the new Eradication, which should seriously contend for three precious points because we all love haste. 20% haste is pretty amazing, especially with an endlessly refreshing Corruption. The haste allows us to better work in Shadow Bolts and Haunts in our rotations. In PvP, who doesn't love a 1.2 second cast Fear? We want this talent.
On tier eight, we have an unchanged Improved Howl of Terror and a more appealing Malediction. This one's easy. If you PvP and you've crazily pursued deep Affliction, pick up Improved Howl of Terror. Otherwise, skip it. If you're a raider, you probably already know that Curse of the Elements now rightfully applies to all schools of magic, with Curse of Shadow rolled in. Malediction also improves spell damage by 3%, so pick it up for PvE. but we'll skip it, too.
Tier nine is where it gets a little tight. There's the duration-nerfed Unstable Affliction, of course. If you're this deep, pick it up. This opens up the phenomenal Pandemic, so put points in those, too. Pandemic is the brilliant method by which Affliction will scale with crit gear and is a good investment because it lets us use all that Destruction gear we have tucked away and lets us legitimately roll on the crit gear we'll be sharing with those smelly Mages.
So that's four points in tier nine. It gets worse. You'll want to put in points in Death's Embrace, which is essentially our version of a Rogue's Dirty Deeds. It works at 35%, which is going to be mind-blowingly good for bosses and actually usable against trash and enemy players. The best part is that it's passive. DoTs and direct damage Shadow spells will simply scale up as soon as our targets start to buckle. If they're already dying, Death's Embrace makes them die faster.
On tier ten sits Everlasting Affliction, which should ease our spell rotations by allowing Haunt and Drain Life to reset Corruption. I wasn't able to test this extensively because it was bugged for a while and I used my remaining time in Beta testing Demonology, but the idea I get is that -- more than Corruption refresh -- it scales up DPS exponentially with each tick. In which case we actually want Corruption to tick for as long as possible before refreshing it and resetting the scaling. You'll want 5 points here, too.
Finally, we get to Haunt, which you should pick up once you get this deep into Affliction. You'll need to squeeze in as many points into the tree in order to maximize it anyway, so don't even bother looking at Soul Link. In order to get the most out of Haunt, you'll need it to land, so make sure you're hit capped. The 10 second cooldown means there's little room for error. If it lands, though, your DPS jumps up significantly. The direct damage component also means it can fill in for Shadow Bolt in a rotation. Haunt isn't as great for PvP because of the long cooldown, but the healing component is a sweet bonus.
Affliction is a somewhat bloated tree. If you're going deep into it, be prepared to spend at least 56 points so you can get the most bang for your buck. This leaves you with 5 points which you can throw into Bane, Demonic Embrace, or even Shadow Mastery. I know it feels scary to commit so much into one tree, but until we get ten more levels, it's not entirely unwise in Patch 3.0.2 to go whole hog Affliction and DoT everything in sight.
Zach helps guide you through the changes in 3.0.2, so you can be enthralled in all the demonic love Blizzard's thrown together. Check out other 3.0.2 Talent Guides, too, as well as everything about the so-called Echoes of Doom.