A common build for Affliction, (other-wise known as the warlock's Damage-over-Time tree,) would be 41/0/20 or 40/0/21. However, Affliction has an amazing amount of flexibility in terms of what talents make up the 41. (The 20 is a bit more set in stone, explained later.) One possibility is this build, which is a general layout in terms of talents.
There are also soloing talents. For example, Shadow Embrace helps improve Drain Life due to Soul Siphon; it's recommended to have at least one point in this talent for this. Also, Fel Concentration allows you to Drain Tank (Drain Life while they beat on you). Improved Howl of Terror is also a soloing/PvP talent because you won't ever really need to use it during raiding/instance runs if it is going smoothly. (This is theoretically speaking, of course.)
Curse of Exhaustion is a PvP talent that is useless in solo play. (Curse of Recklessness is far more efficient at stopping running NPC enemies.) Improved Curse of Weakness is a useless talent altogether, unless you intend on using Curse of Weakness against Rogues. Even in raid situations, a warrior with Improved Demoralizing Shout reduces more Attack Power then Curse of Weakness does with the talent.
Malediction is a talent that many 25-man raids (with heavy caster-user groups) desire and it gives way for an Affliction Warlock for a raid slot due to his utility. Curse of Shadow and Curse of the Elements are one of the reasons Warlocks get their spots (other then top DPS and Healthstones/Summons.) The boost in damage is noticeable and very worth your Curse if you have a couple of casters.
Many little variations include things like Improved Healthstone (Tier 1 Demonology) which can allow you to have multiple Healthstones by having different ranks of this talent (2/2, 1/2, 0/2). Some builds grab Demonic Embrace (Tier 1 Demonology,) which gives you far more stamina at the cost of a Warlock's most useless attribute, spirit. Suppression is an often over-rated talent as it only affects your DoTs when Shadowbolts still compose 45-55% of your damage.
The 20 points in Destruction are generally agreed upon, seeing as the rest are not nearly useful. (Cataclysm saves you minimal mana, far from helpful when you have one of the best classes and specs for regaining mana.)
This build seems to have much less variation then Affliction (or Destruction.) It is good for early Tier 4/Karazhan, and to a lesser extent Tier 5, due to the Felguard's damage output and the additional spell damage you gain. You generally won't want to use this for Raiding.
However, it is the Warlock's soloing talent tree. The Felguard can hold threat/aggro easier then a Voidwalker, and it deals a fair bit of damage too. Recommended only for above level 56 because of Demonic Frenzy -- before that, it is slower then Affliction.
Destruction becomes good when you have the gear to support it. Until then, other builds out-DPS it. 0/21/40 is the most common build, with some possible tweaks here and there. A Fire warlock deals less damage then a Shadow warlock at the same gear/skill level. A destruction warlock will want 202 Spell Hit, 900-1000 Spell Damage and 20% Spell Crit before they really start out-DPSing Affliction. (It's also recommended to get the T5 2-piece set bonus.)
A good leveling guideline would be: 1-56 Affliction and 56-70 Demonology. Some people like leveling 1-70 Affliction, (it's not much slower really,) and others hold off till 58 or 60+ to switch over so their Felguard is more fleshed out, skill-wise.
1-70 Affliction talent layout would go something like this: