The force armour rune for energy armour makes it so you can only ever be hit for 35% of your max health. So the lower your HP the smaller the hit you take, but that's not really what is important. Where it becomes mental is when you begin stacking life regen / life steal.
At 60 without any vitality on your gear you have 4.7k hp so you can only be hit for about 1.6k dmg. If you can get your HP to tick around that per second then you're now one tough mofo. It isn't easy, I've been building towards this for a few days now and I have my 0 vitality, and 1.1k life regen and 400 life steal, I have to say around 1k life regen is when it really started to feel good to use.
This then couples extremely well with diamond skin using the crystal shell rune. This gives you a 20k absorb, which takes into account you only taking 1.6k hits, letting you take insane amounts of damage before that breaks.
From there the rest of your skill / passives is your call really. I use the rest for damage and rely purely on diamond skin in tight situations, with this build simply kiting for a mere 2-3 seconds will see you back on full hp and ready to blast again. Galvanize armour is obviously a great passive for the life regen.
When building towards this, if you're not quite at the 0 vitality I would recommend instead dropping diamond skin for mirror image + duplicates, mixed with illusionist passive. Your HP pool will be too big for life regen to matter, so those images tanking will be much better and can be summoned any time you get hit.
Here is my exact build, I tried to balance AoE / Single target the best I could for keeping the Nephalim Valor buff stacks for bosses:
http://us.battle.net/d3/en/calculator/wizard#akRXSO!YXf!aZaaZY