Warlock talents

Starting at level 10, a Warlock can begin spending talent points to gain new abilities and spells, strengthen existing abilities, and specialize how he/she functions. See the entry on Talents for more information about the Talent system. Warlock Talents have undergone significant changes with the 1.6 patch, and further changes with the 2.0.1 and 3.0 patches.

Some Warlock talent builds have become quite popular. There's a tendency to describe talent builds with the names of their highest-tier talents, or by the numbers of points spent in each tree (30/0/21 means 30 points in Affliction, no points in Demonology, and 21 points in Destruction); the trees are listed in alphabetical order, which is the order in which they appear in the game. Also, there are usually many options available on the way to the top-tier talents; there can be many variations of these depending on each Warlock's individual taste and style.

Do keep in mind that a levelling build is a very different thing from an end game 80 raiding or pvp build. The latter depend on the availability of all talent points as well as stacking stats like Spell Power and haste (which you only do past level 60) to be really effective, so picking a level 80 build right at the beginning and adding points toward it as you level up is a bad idea; you will get very few or none of the benefits of that build until you reach the high 70s. It is better while levelling to target a build for level 40, level 60, level 70 and level 80 and respec to them when you get to that level as these are the stages where key talents and spells are unlocked. With warlocks, you typically need one build to 40 (something like the old SL-SL) that focuses on survivability and uptime without depending on Spell Power, another to 80 that does and a third at 80 for endgame content (raiding or pvp).

See also:
 * Warlock Talent Calculator at Wowhead
 * Warlock Talent Pages at mmo-champion
 * Warlock Talent Calculator at mmo-champion

Which talent tree to choose ?
Warlocks can only take the role of damage dealers (also known as dps), so it's not clear at first moment how each talent tree improves damage or how the warlock's play style changes when choosing talents from specific trees.

Simple explanation
A simple explanation considers that, since the warlock is a damage dealer, then each talent tree must improve damage in a different way. The warlock has many ways of causing damage, like DoTs and curses (ie, "marking" the target with spells that keeps "ticking" or weakening them), channeled spells (ie, a spell that drains energy or mana), damage caused by minions and direct damage spells (ie, spells that have a cast time, followed by a single instant or nearly instant damage burst). Considering this point of view, each talent tree improves damage on the following ways:
 * Affliction: this talent tree improves damage caused by DoTs, curses and channeled spells.
 * Demonology: this talent tree improves damage caused by the warlock's minions.
 * Destruction: this talent tree improves damage caused by direct damage spells.

Since the type of spells improved are different, the spells used by the players will vary according to the tree.

Talents as task solvers
A second view of talent trees is considering that there are many different tasks that the warlock may want to do in the game and that certain tasks are better accomplished by certain talent trees. Consider the following tasks: leveling, doing quests, farming, playing PvP and playing with a group in dungeons and raids. Each task may be done better by fullfilling certain essential requirements:
 * leveling, questing and farming: requires fast player versus environment game, which translates to both medium to high damage and low downtime due to lack of health or mana, that is, some amount of survival capability.
 * playing pvp (many types): there will be cases when good damage is necessary and other cases where exceptional survival is more important than damage (specially when a group with well defined roles is not available).
 * playing in a group: the warlock has a well defined role here, maximal damage is desired.

How each talent tree is related to each task and which task is better fullfilled by each talent tree ? If we consider that we would only pick talents from a single tree, the following discussion would apply:
 * Affliction: besides improving damage, affliction also improves healing generated by certain DoTs and drains. Also, it improves mana efficiency of those spells, as well as improving ways of generating mana. Affliction has a good spell damage, coupled with moderate survival support, so it's well suited for leveling, questing and farming. The DoTs and drains, although improved, don't have excellent dps on single targets, so affliction warlocks should fight against multiple enemies at any time, which further improves farming speed. This also applies to PvP: affliction warlocks may curse many enemies at a single time when in a group, but may have trouble when solo fighting against high dps enemies. Raids are possible and exceptional dps can be achieved, but affliction warlocks should also concentrate on cursing enemies so that they're weakened and other players are able to improve their damage.
 * Demonology: this tree improves not only minion's damage, but also other minions abilities. For example, voidwalkers may tank better and the felguard becomes available a high damage tank. Together with health improving and damage mitigation talents, it's possible to increase the focus on the minion and greatly improve the warlock's survivability. Even the warlock may transform into a demon, becoming a hybrid warrior warlock for a few seconds. The demonology is specially suited to pvp situations where extreme survival is a must. It's not as suited for leveling as affliction, because there are so much points to spend in survival, that damage dealing is not improved in the same proportion. On the other hand, it's good against single targets, to the point that it's possible to solo elites with a Voidwalker or Felguard that would otherwise require a 3 or 5 people group. Again, since the spell power is not improved very much it may not be well suited for playing instances and raids.
 * Destruction: this tree is focused in improving damage, with a few talents for mitigating damage and healing. This bends much more towards dealing damage, so this is well suited for raiding. Destruction is not suited for leveling, because, even though damage is greatly improved, downtime is caused by lack of mana. PvP may be well suited in the opposite case of Demonology, that is, when the goal is to kill the opponent as fast as you can, leaving the responsibility of survival to a partner, for example.

How this translates to practical, real world talent builds ? If you need to go leveling or making quests, affliction is by far, the least downtime, most mana efficient talent tree, so get as much points as you can. If you need a lot of survival when playing pvp, specially against damage bursts, the demonology offers the most health improvements and damage mitigation, so get lots of points in demonology. If you play pvp, but doesn't require a lot of survival, spend some points in damage and some points in healing in affliction or destruction. If you need guaranteed damage in raids, choose destruction talents. Alternativelly, if you think you can cope with more complex DoT rotations (thus dealing with more varied cases) and still mantain great damage in raids, put points in affliction.

As a useful hint, even though the best talents are deep in each tree, complementing some tree in higher levels with another that improves something that the original tree lacks is almost always done in popular builds. For example, the "Shadow embrace/ruin" is a 56/0/15 that spends 15 points on a single destruction spell to complement damage for this affliction spec. Similarly, the "PvP-Destro" 0/20/51 improves the high damage pvp spec with many survival tricks.

What about playing with the "wrong" build ? The above discussion does not prove that certain builds are correct and others are wrong, they only relate each tree with certain tasks. So, a warlock would want to level up with destruction and cope with high downtime, simply because he finds boring casting DoTs. That wouldn't be a "wrong" build, that would be the right build for him.

Affliction
The Affliction tree gives a Warlocks specialization in stable damage over time spells with more powerful curses and drains, better DoT ability, and in the end more powerful Shadow spells in general as well as a new way of recovering mana. There are also two additional DoTs and a new curse.

Demonology
The Demonology tree gives a Warlock more powerful demons and conjured Stones, as well as more stamina and some buffs that take effect when the demon is present. It also increases the effectiveness of enslaved Demons and end-game summons, and in the end there's a new way to make the Warlock very hard to kill.

Destruction
Destruction improves the direct damage spells of the Warlock. There are talents to increase the speed at which your pets attack here, as well as to improve your damage-dealing spells, their chances to get critical effects, and the damage done when critical effects occur.