I went with a completely different plan than most people for a witchdoctor build I plan to be leveling with multiple people but I opted to go with a pure poison build heavly relying on my gargantuan to tank. http://us.battle.net...iTfQ!bZc!bYYYcb
If all goes to plan I can spam my poison abilities while my gargantuan tanks thanks to bad medicane and jungle fort thats 40% less damage done if they stay poisoned and if my gargantuan is in the fray at all times with big stinker that shouldn't be a problem. I do feel that this is NOT a good inferno build but should be really good for normal NM and even hell.
You'll probably want some more CC outside of the Garg in case you get mobbed. With all the AoE you've got being able to pick off threateningly close mobs becomes difficult. The Zombie Bears take care of that except that they're a bit on the expensive side. Which brings me to the other concern, mana. You may not have enough of it to spam everything. Try reading some of the other build/criticism threads for some general method for refining your build. Some builds I've been looking at also utilize the Garg for CC but try to maximize overall dps by several stacks of DoT's and a good single-target skill like Darts/Splinters.
If you've still got questions, feel free to ask, there's help enough here even if some of it is getting jaded.
I like the concept of your build, but it needs some refinement. You have too many attack spells. You can only cast one attack at a time, so I would drop Acid Cloud, Zombie Charger, or (maybe) both. The gargantuan will make a pretty decent tank, especially with Jungle Fortitude and Bad Medicine, but there will be situations when you need a bit more than that.
Grasp of the Dead, Horrify, Spirit Walk, and Hex are all good options for abilities with fairly short cooldowns which can help keep enemies off your back.
EDIT: Also, note that Jungle Fortitude and Bad Medicine combined do not equal 40% damage reduction. The reductions are multiplicative, so you'll be taking (1 - .2) * (1 - .2) = .64 of normal damage, or 36% less damage.
Even if I do find a poison resisted mob in NM/Hell the ease of switching spells on the go is ridiculously easy compared to just being screwed in d2 the build is clearly focused on aoe/poison damage as for mana issues there may be some I dont think any spec is gonna be able to spam there abilities but ill be able to have a varity of dots/poison damage going at once that allows me to play more of a mage/support rather than a support/mage if that makes any sense lol.