Affliction is actually easier than Destruction and Demonoloy now. It has been nerfed into the ground baby.
Affliction is the way to go for levelling. DoT up a bunch of mobs and keep a fear rotation going. With the siphon life effects and Drain Life, you can literally do this for an eternity.
This is some advise I gave someone else for Warlock'ing at level 80 (Raiding):
Well, as for a spec, take a look at my Lock's Destruction spec
here. This spec is not very difficult. Your rotation in a raid will be: Curse, Immolate, Chaos Bolt, Conflag, Incinerate. Then repeat Incinerate until Conflag or Chaos Bolt is off cool down. Always keep Conflag and Chaos Bolt on cool down and try not to refresh your Immolates too early. Remember, if Immolate is up on the target, it buffs the damage of Incinerate. When you cast Conflag, you will get a buff called Backdraft with 3 charges on it. This means that your next 3 casts of any Destruction spell will be hasted (30%). Try not to use one of these buffs on Immolate as it will decrease your DPS (not by a huge margin tho).
As for curses, you will use Curse of Elements if there is no Boomkin, Unholy DK or Shadow Priest in the raid. Otherwise use Curse of Doom or Curse of Agony if the boss will die in under a minute. CoA is not a priority. So it it drops off, it is not a train smash as it's DPCT (Damage per Cast Time) is not very high.
The pet of choice for this spec is obviously the Imp. Blizz have thankfully changed some pet mechanics and gave Warlocks the Fel Synergy talent (heals pet for 15% of the damage you do) so it is much, much easier to keep your pet alive. Unphase your Imp before you get buffs so he can get them as well.
I hate PvP on my Lock. A Warlock is extremely soft with very few defensive abilities. Melee will always train you and a Rogue will single you out first (even when a healer is present). I don't find it fun being constantly being locked down by Melee.
As for gear, hit is your most important stat until you are hit capped (17%/446.25 hit rating). You will get 3% from Supression (talent in the Affliction tree). So you can aim for 14% (367.5 hit rating) to be hit capped on your own or 11%(Horde)/10%(Alliance) to be hit capped in a raid. It is up to you which route you want to take. Calculation = 26.25 hit rating per 1% spell hit at level 80.
While I was gearing up, I picked up a ton of haste. I landed up with 500 Haste and had about 19% crit. Incinerate is haste capped at 1 second. When I Conflag, my Incinerates were not benefiting from all my Haste so I re-geared to push my crit higher. I therefore prefer to stack my gear as follows: Hit (until capped) -> Spell Power -> Crit -> Haste -> Spirit -> Int -> Stamina.
As for Glyphs with this spec, Incinerate and Conflag are essential. Use the Glyph of Immolate if you are under 500 spirit. Then switch to Glyph of Life Tap when you reach 500+ Spirit.
I suggest you play around with your spec and gear to see what suits you the best.
My Warlock is my alt so don't be too harsh on her gear.