Quote:
Originally Posted by Glitchless
Computing the probability that at least one of the following events will occur:
P(a or b ... or z) = 1  P(!a and !b ... and !z)

Quote:
Originally Posted by Sporky
... what does the exclamation point mean in this?

The ! means nota, notb, etc.. It is the chance that the event will NOT happen. If you have a 69% extra chance to crit, there is a (10069=)31% chance that you will not.
Kerrlahg has shown this very nicely above.
Another thing to consider is Epic leggings and Bows. Each add another 1% extra chance.
With those, Level 100 skills, and 6% for a rank 5 rune, the highest I get to is 58.956%
The first hit at this point is of course always a crit if you have lvl 100 in Two Handed. You probably still have to hit with the attack first though.
I don't know the order of events for determining hit/miss, dmg, crit, double attack, etc... though. For example, if the First 'Attack' is a Double Attack, would both hits have the bonus to being a crit?