How much hit should I aim for in PvP?

Title says all of it. What is the Exact Hit Number I should aim for?

Thanks :D
4%. No more, no less.
what is the exact hit rating needed to get to 4%?
If you go to your character tab and scroll down to the spell stats you should be able to see. You want to be at 0.0% miss rating for level 85 enemies.

Just scroll over the hit stat in the spell tab and it'll show you your miss chance for each level enemy. Download the addon RatingBuster. It'll tell you how much % you gain per amount of hit on any item. Every % of hit will be deducted from your chance to miss the enemy.