there´s been a similar topic last week I think, here´s my postshttp://us.battle.net/d3/en/forum/topic/7708952515#16http://us.battle.net/d3/en/forum/topic/7708952515#18
Basically 75% is the barb cap not including Battle Rage, Ruthless and Wrath of the Berserker, only those 3 skills break that cap to a general 93% cap. Things like +WW crit chance on a Stone of Jordan go above that so it´s possible to have 100% with WW, Overpower, Revenge, Seismic Slam and Hammer of the Ancients.
Here´s the crit chance items/skills:
5% innate critical hit chance
6% ring1 (potentially another 7% from Natalya´s 2 set bonus)
1% inna´s temperance (pants)
1% tal rasha´s brace, inna´s favor (belts), pride of cassius, lamentation (mighty belts)
= 56% from gear (63% for Natalya´s 2 set bonus)
+there´s also some bad 1% crit chance weapons but you don´t want to use those
10% Overpower - Killing Spree
10% Revenge - Best Served Cold
10% Wrath of the Berserker
10% Weapons Master - Axe/Mace equipped in main hand
3% Battle Rage
3% Anatomy (Scoundrel skill)
= 51% from skills
As I said, only Ruthless, Battle Rage and WotB can go over the 75% cap.
Note that if you look at people´s profiles what you see is only the crit chance on gear, the actual value while they slay monsters is usually much higher thanks to skills.
Critical hit damage maximum values hmm, base +50%, MH Weapon +210% (assuming 1.0.7 marquise emerald and innate +100% crit damage on weapon), OH weapon +210%, Witching Hour +50%, Ring1 +50%, Ring2 +50%, Gloves +50%, Amulet +100% (+50% more for Endless Path set), Ruthless passive +50%...that´s about it, hope I didn´t forget anything.
EDIT: forgot shield...