http://us.battle.net/d3/en/profile/zushiba-1922/hero/3594324

I was stacking life regen for all of act 1, act 2 was super painful and act3 might as well be impossible. At it's height I had around 1800ish unbuffed life regeneration.

All resist/physical resist still don't seem to help much to keep me from being insta-gibbed. I'm open to suggestions on build/gear.

I'd suggest getting life on hit... It can be expensive, but slightly cheaper on amulet.

Have you tried using Force Armor? If you're often getting hit for over 1/3 of your life then it will be better than prismatic. On the other hand, if you're getting hit for over 199% life then you'll die anyway (but then the answer is that you need better gear). I'm not a fan of FA myself since I like to play balanced, so if I was playing that toon I'd get some gear with more all res. I'd try to average at least 50 AR per armor piece for A2, 60 for A3. Note that if you manage to keep your INT very high you'll have more leeway here. If you were going to use FA as a glass cannon, you're gonna need a lot more DPS.

Don't worry about losing life regen if you can gain significant armor/AR/vit. If you get those higher you'll have more time to wait for potion cooldown, grab health globes, etc. You should have some form of regen/LoH/steal, but it doesn't have to be extremely high if you have good defense.

I would definitely dump galvanizing ward unless you end up re-gearing with very low regen or LoH. 300 life per second isn't usually as helpful as other options. Arcane Dynamo works extremely well with venom hydra.

I would trade your familiar for blizzard, or at least some high damage skill like arcane orb so you can actually utilize your AP for something. Blizz makes it easy to force mobs to slowly run back and forth over venom pools.

I would use teleport/fracture in place of mirror images because I like the mobility while retaining the decoys. I'd at least use a more defensive rune. I don't feel the 10% damage makes them worthwhile unless you are using it for tactics like extra frost nova casts.

Lastly, I'd use the enchantress. I'm assuming you're using scoundrel with the cold bow to slow enemies. Blizzard will do the same thing with way more DPS, then the enchantress will give both IAS and a 15% armor boost (and swap to erosion since disorient won't last long in inferno). The armor bonus stays even when she's knocked out.

Yeah I have been using Force Armor, I don't remember why I switched to Prismatic, I think I was testing something at the time and I've been focusing on my Barb recently so I haven't been playing my Wizard as much so I probably just have switched it back.

I'll definitely give Arcane Dynamo a go. I was using the the familiar for extra survivability but it doesn't seem to do anything for me.

Should I be looking at any specific type of weapon for the enchantress?

I didn't notice earlier that you have no movement speed on your boots. You can get a pair of sage's seekers for relatively cheap (they recently jumped in price along with brimstone prices, hopefully they'll settle back down to 200-250k). You'll drop some INT and VIT, but you'll gain a good amount of AR and armor to make up for it. I find MS to be the most helpful stat when I'm playing a ranged build. If you can successfully run away from mobs, you won't need to use 4 skill slots on defensive based abilities (perhaps I should say 3 slots since energy armor is required for almost any build).

I use the snowbound rune on blizzard so I have the freedom to cast it all over the screen as needed. There are some elite fights where I'm barely attacking, I just run around to avoid damage and let blizz/hydra do all the work. If you need to run around a lot, you may want to use magic missile/seeker rather than electrocute so you don't have to waste time aiming properly (the usefulness of seeker depends on your skill/mouse precision).

For the enchantress I happened to find a 1200 DPS staff, but keep in mind she can also use certain other 2H weapons like swords/axes/maces (not polearms or bows). Your top priority of course would be to get her INT and VIT overall. You can focus on one vs the other based on if you want her to do significant DPS, or if you just want her alive to keep using her skills. Forceful push is really nice for ranged classes. Since almost nobody is using 2H weapons they shouldn't be too expensive.

Are you using the Templar for extra regen and heals? Might want to look for a similar weap but with life steal for extra healing or just more DPS so you can kill faster and avoid getting damaged.

Yeah I'm finding the same issue with life regeneration. It just doesn't seem to scale as well into later acts.

something i found that helps is to re-stat vitality with all resist. that way your max hp gets lowered while your effective hp stays the same. The final result means your life regen is worth that much as a % heal per second.