Diablo – Which area in Act 1 can I gain Nephalem Valor the fastest

The entire Nephalem Valor concept has been removed since Patch 2.0.1 (live on Feb. 25, 2014). Along with this change, two new concepts have been added to the game (Official Patch Notes):

Pools of Reflection have been added to the game

• Pools of Reflection provide a 25% bonus to experience
• This bonus persists until you reach a set amount of bonus experience (equal to approximately 10% of the current amount of Paragon experience needed to reach the next Paragon level) or your character dies
• Gathering additional Pools of Reflection bonuses increases the amount of total experience bonus a character can receive until character death, stacking up to 10 times
• This experience bonus persists on logout

Nephalem Glory has been added to the game

• Occasionally during battle, monsters will drop Power Globes when damaged or killed
• Power Globes grant the Nephalem Glory buff, which causes players to deal additional damage in the form of golden lightning bolts and increases their movement speed for a short time
• This buff can stack up to three times

For the Critical Mass passive, what is meant by the "chance" is that it is determined by the proc coefficient of the spell you cast. Single target spells have 100% "chance" to reduce the cooldown by 1 second while AOE spells have differing sets of proc coefficents by spell AND rune. There's a few sites that break down proc coefficents of various spells which applies to crit chance as well as return on LOH. Here, and here. Luckily people with more patience than me seem to have most spells crit proc chance figured out.

Some useful proc chances for popular wizard spells:

Hydra: 0%, Hydras never proc
Magic Missile / Seeker: 100%
Shock Pulse / Piercing Orb: 25% per target hit
Blizzard / Snowbound: 2% per tick per target hit
Energy Twister / Wicked Wind: 10% per tick per target 
Explosive Blast / Chain Reaction: 11% per target hit per explosive (of 3)

I've recently been trying the Windup Wizard/CM build which still seems pretty effective, and a bit silly (in fact it was the easiest way for me to beat inferno Ghom). From personal experience I've found that on my wizard, when I run over 40% crit chance while using a build like windup wizard, everything is off cooldown pretty much all the time.