Hey, I will post all the most popular's 3.1.0 PvP Builds in this thread, there might be other good builds, these I recommend tho.
Mage
Frost+Improved Counterspell This is what I prefer, Im using it atm, and all I can say it is good.
Death Knight
Unholy/Blood
This build I'm using, tho if you want the gargoyle you can choose between Mark of Blood, or Gargoyle
Hunter
Survival/MM Basic Survival/MM Build, nice DPS
Druid
Basic Feral Build
Basic Moonkin Build
Full Resto Build
Warrior
Basic Arms Build
Warlock
Destruction Build
I don't link affliction, because this one is that you should go into [Destruction pwns affliction nowadays]
Shaman
Resto/Enhancement
Elemental Build
Full Enhancement
Rogue
Combat Build
Mutilate Build
Priest
Shadow Build
Deep Disc
[NOTE: If you got anything you want to ask, or if you have any build you want to be linked, just post in this thread, and I make it happen]