Hit Rating

No hit = no dps
Hit rating cap
In the context of stats, the term "cap" refers to the point at which equipping more of a particular stat will have no additional value. For hit rating the cap usually discussed is in regards to raid bosses. For example, once you reach or surpass the hit cap, you will never miss an attack against a raid boss unless you are under the effect of some debuff that reduces your hit chance (for example, Attumen the Huntsman's curse).
As shown above, your base chance to miss a raid boss while dual wielding is 28% with auto-attack on both hands. Your base chance to miss a special attack is 9%. For each 15.77 hit rating you equip, you reduce your chance to miss by 1%. Thus we can calculate hit caps for auto-attack and special attacks:

All melee
Dual-wield auto-attack: 442 hit rating
Special attack or Single-wield auto-attack: 142 hit rating

Paladins
With Precision (Paladin talent): 95 hit rating

Rogues
Dual-wield auto-attack, with 5/5 Precision (Rogue talent): 363 hit rating
Special attack, with 5/5 Precision (Rogue talent): 64 hit rating

Shamans
Dual-wield auto-attack, with 3/3 Dual Wield Specialization and 3/3 Nature's Guidance: 300 hit rating
Special attack or Single-wield auto-attack with 3/3 Dual Wield Specialization and 3/3 Nature's Guidance: 95 hit rating (Dual Wield Specialization does not affect Single wield auto-attacks or Special Attacks when single-wielding.)

Warriors
Dual-wield auto-attack, with 3/3 Precision (Warrior talent): 395 hit rating
Special attack or Single-wield auto-attack, with 3/3 Precision (Warrior talent): 95 hit rating

Hunters
Special attack or ranged auto-attack, base 142 hit rating (9%)
Special attack or ranged auto-attack, with 3/3 Surefooted: 95 hit rating

When raiding remember to take in account:

The presence of a Draenei Hunter, Paladin or Warrior in your party. Their Heroic Presence racial ability gives +1% chance to hit with physical attacks thus enabling you to swap 15.77 points of hit rating for more useful stats.

The presence of a balance druid with 3/3 in Faerie Fire(Balance) in your raid. This ability gives +3% chance to hit with physical attacks thus enabling you to swap 47.31 points of hit rating for more useful stats.


Spell hit rating caps for level 70 (casters)

http://www.wowwiki.com/Formulas:Spell_hit_chance#Spell_hit_rating_caps_for_level_70

Look through the table to see if you have any talent that adds to your spell hit

*All these can be found in http://www.wowwiki.com