I pretty much agree with lathais. Decide if you want to run around doting everything (affliction),send in felguard with some dots (demonology),or act like a mage (destruction). Each one has it's strengths along with weaknesses. Affliction pvp wise, You got 3 instant cast damage dots,Instant Howl of terror,dark pact to keep mana coming to you,You can kite with this build as well with Curse of exhaustion and the unstable affliction which pretty much protects your other dots from being dispelled apart from it's damage. Demonology can offer a few things to.That felguard is pretty awesome! If used really well, you can get to the top of hk andmost damage done 61-69 bracket,70 bracket you drop down a bit but the output is great!!Apart from that you'll have soul link which offers you more survivalbility. Also, you'll get the perks if you gone full demonology when having a demon out offering,increased damage,resistances,more DR depending which demon you have out. Now destruction I am not really familiar with..Basically think of fire mage. But like Lathais said..all have great damage output. Decide how you want to play your lock.