I've been having a lot of fun with this one

http://us.battle.net/d3/en/calculator/barbarian#bZXVSY!dbY!aYaaZZ

It works great in NM, I've yet to see how viable it is in Hell. Jumping into huge mobs, wrenching them, charging back and forth until there's no more mobs left. The enemy ends up just disintegrating.

Special monsters - especially the ones with freeze makes things more complicated however. Anyone else been having fun with Merciless Assault?