Farming XP

I've tried farming XP (and magic items) on lvl 50 and lvl 56, here is my experience:

lvl 50 - Azmodan Nightmare

Time: 10 min

XP: ~150K

Start at the last quest of Act III, go through 2-3 rare/champ groups, kill the boss. It took me 6-10 mins per run (depending on champs). After finishing the boss you got 45K for quest and then immediately after you got another 45K for the next quest!! Plus ~60K from killing monsters. Overall a really nice easy run, I levelled from 50 to 51 in about 40 minutes (510K XP).

My stats for this runs:

13K health

2410 damage

88% magic find

lvl 56 - Zultan Kulle Hell

Time: 3-5 min

XP: ~110K

I've killed him first time very fast and was pleased to get 98K for quest, so I stopped and farmed him till level 57. Pretty easy and fast run in my setup. Slowing-kiting-killing golems, then dodging tornadoes and finishing the boss. There are no monsters to kill before encounter, you basically spawn straight to the boss.

My stats for this run:

20K health

5600 damage

104% magic find

http://us.battle.net/d3/en/calculator/wizard#iRXQSO21bYaaaaZ!YfU!abZZZb

Temporal flux passive is super important - without it golems reach you and make life hard. After golems down, the mechanic is simple - wait for diamond skin and teleport cooldowns, run (not jump) to the boss, use diamond skin and burn with disintegrate (or whatever), then jump away and repeat. All this time hydra and your follower also doing some dps. Oh and note Wormhole rune on teleport - without 3 jumps it will be much harder to dodge some of Kulle's stuff!