0 CD Sacrifice build is crazy expensive, but like really REALLY expensive.
I'm using some kind of variation on it, only use it to farm mp0 or mp1. It's really fun to play, you need a lot of pick up range though, I have 48, you basically sacrifice the dogs that respawn with circle of life, they leave health globes, those proc Grave Injustice, that keeps your mana topped up so you can spam Acid Cloud AND sacrifice for pretty high burst damage + increases your damage. (can switch Acid Cloud with bears if you want but I like the LOH proc on AC)
With the high pick up radius and Circle of Life you should be running with 3 dogs most of the time but you can also swap pierce the veil for Grave Injustice, works great with the huge pick up radius and keeps the cooldown on zombie dogs pretty low.
http://eu.battle.net/d3/en/profile/koji-2671/hero/964675
Build is not so expensive and works great on low MP.