Alright, I am going to combine SniperWong, RayGorn, MannerCookie, and my own stuff to the Witch Doctor section.
For my own notes, I feel that these key-bindings are a must-have, but I know it depends on conditions against good Witch Doctors depend on their methods. If they avoid haunting you, Superstition isn't as effective for fury generation, but it is still a great way to mitigate damage.
Anyway, let's start with the basics: http://us.battle.net/d3/en/calculator/barbarian#cPkXUi!cUe!acYYaZ
1) Practice this build before testing it against a good witch doctor. The biggest change is in the removal of an automatic melee attack generally found in your right-click. To activate Rend, you will need to hold down Shift + Right Click. It took me most of the night to turn my concept into muscle memory, so there will be a learning curve. Due to our inability to hit for damage, there's no reason we should have Bash, Frenzy, or Cleave in our key bindings. By practicing this set-up, it opens up room for WoTB (rune of which I am still trying to test) and allows for us to counter their hexes and fear procs.
2) I have two ways to mitigate their attacks; Sprint's Rush and War Cry's Veteran's Warning. One could conceivably put in Striding Giant for WoTB, but I feel that the skill is best used for massive damage through Rend's critical hits.
3) Immortal King's Irons, Triumph, and Stormshield are absolutely essential. The reason why is that they all have melee damage reduction. From my understanding and testing, melee damage reduction actually mitigates the damage you get from their pets. By how much, I'm not sure yet. But my survivability improved as I got used to the key bindings and the gear. For the record, you will be expected to have a third Immortal King's piece to gain the three-set bonus.
4) Superstition allows you to take some damage to accrue our class resources. By doing so, it allows you more time to properly use your skills and 'conserve' for an opening when your opponent is vulnerable. When you're haunted or being hit with spirit barrage, the fury generation is so quick, I can't burn enough fury to get rid of it.
5) Rend resource cost reduction. Get it. Now. On your Immortal King's Tribal Bindings and Stone of Jordan. Get it. Get it. Get it. The prices are going to sky rocket for them. By reducing the fury cost to 10, you have more room to spam Rend until you get a critical hit.
6) Rend and Run. It's unfortunate, but it is the only way to counter Witch Doctors. You cannot tank and fight. If you can, I haven't seen anyone do it. Sprint allows you time to regenerate your health and to accelerate fury resources if you're being haunted or hit with Spirit Barrage.
7) Leap has three (potentially four) utilities: It allows us to escape from ugly situations; Call of Arreat draws your opponent in for a Rend hit; Can hide Sprint's tell-tale direction you are kiting to. It also does some damage as well when you hit them. Near the end of the video below, my finishing move was a Leap crit in WoTB.
8) Some ability to predict your opponent's movement as well as some trickery and manipulation of the battle will be key to winning. It won't be easy, but knowing your opponent's combos and general location/movement will allow you to take advantage of a Rend and Run.
9) WoTB is there for countering hexes and to finish them. Use it sparingly and judiciously. You will see from my videos I popped it too early a few times. The skill is where I used to have Rend.
http://www.twitch.tv/acrimony1561/b/360443374 (the game play gets better as the video goes along; skip to 19 minutes if you want to see the potential for this).