Changes

The Barbarian has a number of skills that increase the % damage of his critical hit, and a few interesting skills that boost other properties (such as fury generation rate and defense) when he scores critical hits. There aren't any known skills (yet) that increase his chances to score critical hits, though.

[[Juggernaut_Skill_Tree#Inspiration |Inspiration]] "increases critical hit damage by 3% and increases the damage of added hits by 5% for 15 seconds." It's not known what this description means by "added hits." The bonus to critical hit damage seems very small too. Just 3%? Would that make the total bonus +103% damage? Or do Barbarians have some value other than +100% for critical hit?

[[Battlemaster_Skill_Tree#Battle_Rage |Battle Rage]] is a buff that temporarily (15 seconds) increases damage by 100% and critical hit damage by 30%.

[[Battlemaster_Skill_Tree#Hammer_of_the_Ancients |Hammer of the Ancients]] boosts critical hit damage when using this active skill.

[[Battlemaster_Skill_Tree#Critical_Attacks |Critical Attacks]] this passive skill boosts critical hit damage by 20%. This skill apparently boosts all critical hit damage for the Barbarian, even that inflicted by non-special attacks, and skills from other skill trees.

[[Battlemaster_Skill_Tree#Deliberate_Defense |Deliberate Defense]]. "On a critical hit, +10% armor for 15 seconds." This skill is a sign of how integral Blizzard wants to make critical hits to the game. This one boosts the defense when a critical hit is scored. It would seem to directly incentivize standing toe to toe with enemies and smacking them in the face; the more critical hits you score, the less likely they are to hit you back.

[[Berserker_Skill_Tree#Savage |Savage]]: This passive skill "Increases Fury generation 30% for 8 seconds after scoring a critical hit."

The effect of Most wizard skills seen at Blizzcon (October 2008) displayed the bonus provided by a critical hits hit of that type of damage are listed on the hover description of lots of Wizard spells(cold, lightning, etc), but as of Blizzcon (October 2008) there were few fewer skills that actually detail specific bonuses to boosted or from affected the frequency of his critical hits.

[[Storm_Skill_Tree#Thunderstruck |Thunderstruck]]: Increases the critical hit chance of all lightning spells by X%. The bonuses listed on this passive skill as of Blizzcon (October 2008) started at 5% and increased 5% per skill rank. It's not known what the base bonus to critical hit is, for the Wizard. This skill might increase it from 0%, or Wizards might have an inherent bonus based on their Clvl, or attributes, or there might be bonuses to be had from equipment. [[Storm_Skill_Tree#Frost_Nova Frost Nova]]. Projectiles have an additional 25% chance of a critical hit. Frost Nova doesn't deal very high damage, and it has a very long 12 second cool down time, so the attraction of critical hits here is clearly from the cold. (Critical hits from cold damage freeze targets.) [[http://www.diablowiki.net/Storm_Skill_Tree#Deep_Freeze Deep Freeze]]: Increases the critical hit chance of all cold spells. This passive spell adds 5% chance at Rank 1, and more at higher ranks. [[http://www.diablowiki.net/Storm_Skill_Tree#Lethal_Energy Lethal Energy]]: Increases the chance to score critical hits with melee and spell attacks. Grants a 5% bonus at rank 1. This seems like a very powerful skill, if it indeed works for all spells, including those in other trees. It's a fairly high level skill though, and would require a substantial investment into the Storm skill tree to enable it, but it might still be worth it.