Rogue 80 Critical Strike Cap

What is Critical Strike?
 A Critical Strike "Crit" is a strike which deals 100% bonus physical damage when a target is attacked (in a Rogues case) with melee weapons.
Calculating what your effective Crit on a target can be a little daunting due to the factors on the combat table effecting the outcome!

We will attempt to simplify it here! Want more? Check out the guys of at Elitist Jerks. Great stuff, but as usual take your PHD in Rocket Science and rations for the duration!

Critical Strike Rating
For every 1% Critical Strike chance there is 45.91 rating.
As of Patch 3.02 this effects not only Melee attacks but Spells also!
That's it! Our poisons are Spells! Bonus!

Rogue Critical Strike Cap
Ok! A level 80 Rogue with White Attacks on a level 83 Boss has a fixed 24% chance of being Glancing Blows.
Not much we can do about that one.

Now time to skirt around the formulas and get to the heart of Crit caps for Rogues.
An attack table is made up of % chance to:
Crit+ Hit 
Miss
Dodge 
Parry
Block
Glancing blows

Were attacking the boss from behind (If you are not get thee to a tank forum :P) therefore the Boss cannot Block or Parry! So, ignoring those and knowing Glancing Blows are fixed at 24% we have:
Crit+ Hit
Miss
Dodge
Glancing Blows       24%

Basically we have a 76% chance to Crit now less x% Miss chance and x% Dodge chance.
Therefore if your Miss chance is 0% and Dodge chance is 0% your (76-0-0) Crit Cap is 76%.
If you Miss chance is 10% and Dodge chance is 5% (76-10-5) your Crit Cap is 61%
That's all folks!
We discussed how to mitigate Miss (Hit Cap) and Dodge (Expertise Cap).

To sum up, its wise to:
1/ Cap Expertise
2/ Cap Hit up to White hit
3/ See where your Crit is.
4/ Throw anything extra from then on into hit.