What is the best talent tree for a Warlock when I want high damage output?

Solution 1:

Short answer: Destruction.

Long answer: Given your desire to hit harder and your problems with remembering to cast curses, I would argue that rules out both affliction and demonology. Destruction is going to give you the best DPS output generated from your toon in single hits, which seems to be for what you are yearning. With demonology, your DPS will be split between you and your pet.

If you're the kind of person who likes sheer numbers, you should check out this thread on Elitist Jerks. After running some simulations with SimulationCraft, the following was observed:

• Affliction currently puts out the most DPS, followed by Destruction, then Demonology. This is true for pre-raid or post-raid.
• Destruction outpaces affliction in fights with heavy movement.
• Taking into account the coming PTR changes, it looks like Destruction will outpace Affliction in Tier 11 gear overall.

Solution 2:

All three trees are capable of doing nice dmg and can be used to quickly level. Blizzard tries to keep them on par with each other, so it doesn't matter which one is better now: the difference will be small and might swing the other way next month.

Affliction kills by casting dots, and includes lots of self-healing to survive till the mobs drop down from the dots. As it takes much longer to kill a single mob, you'll be better off fighting multiple mobs at the same time. Don't use the voidwalker to tank the mobs; you'll heal enough to overcome a few hits. The succubus is, I think, the best dps pet. [EDIT: the felhunter is the best affliction pet]

Demology puts more emphasis on the demon pet. I don't have much experience with this, but it seems to be the best one if you want to solo elite mobs and other group quest bosses. Felguard is the special demon for this tree, and it rocks!

Destruction is about the big nukes, and plays more like a mage.

Pick the one you like the most. After all, it's just a game ;)

Solution 3:

Ignoring that you have problems playing a warlock with its damage overtime spells, which i am sure you will overcome if you want to play a warlock and not a mage.

Affliction, and some sort of a training wheels priority hint warlock addon (no matter what spec you choose) that suits your ui.

once you have mastered soul swap, get to the level where haunt / fel flame mob transitions are pretty simple and on questing mobs a simple macro will do all the 'remember' stuff for you until its muscle memory.