Thanks to Akrios for the guide =)
A Guide to Gemming and Enchanting Gear for PvE The following is a basic guide to both gemming and enchanting your gear for the highest possible PvE dps. A PvP gemming guide will follow shortly. Keep in mind that all epic gems are available on Sunwell Island at the cost of 15 badges of justice, from bosses in Hyjal, Black Temple, and Sunwell Plataeu, and from your local auction house for a few hundred gold.
Meta Gem
Relentless Earthstorm Diamond
+12 agility & 3% critical strike damage. Require 2 red gems, 2 blue gems, 2 yellow gems.
(Note - having an orange gem will count as having 1 yellow gem and 1 red gem. The same is true of purple and green gems.)
This is the best choice for any PvE situation. It provides the highest damage output. The meta that provides haste suffers from a hidden cooldown of 40 seconds and is inferior to this meta in every way.
Combat spec gem selection:
Red Sockets
rare: 4 agility / 4 hit - Glinting noble topaz
epic: 5 agility / 5 hit - Glinting Pyrestone
Yellow Sockets
rare: 8 hit - Rigid Dawnstone
epic: 10 hit - Rigid Lionseye
Blue Sockets
rare: 4 agility / 6 stamina - Shifting Nightseye
epic: 5 agility / 7 stamina - Shifting Shadowsong Amethyst
Mutilate gem selection:
Red Sockets
rare: 8 agility - Delicate Living Ruby
epic: 10 agility - Delicate Crimson Spinel
Yellow Sockets
rare: 4 agility / 4 hit - Glinting noble topaz
epic: 5 agility / 5 hit - Glinting Pyrestone
Blue Sockets
rare: 4 agility / 6 stamina - Shifting Nightseye
epic: 5 agility / 7 stamina - Shifting Shadowsong Amethyst
Notes:
Buffs such as Blessing of Kings are what make agility superior to attack power.
Unless the socket bonus is stamina, it’s best to gem for socket bonuses.
You should not use more than 2 blue gems if you are maximizing dps. These are only being used in order to satisfy a meta requirement. After this point gem 10 hit, 5 agility / 5 hit, or 10 agility depending on how close you are to hit cap, or 10 agility if you are mutilate.
When gemming, take note of hit cap to ensure you are not wasting statistics. Past a certain amount of hit, you will not gain anything.
Hit Cap for raid bosses:
0/5 precision: 442
5/5 precision: 363
Enchanting Gear
The following are the highest dps enchants available for PvE
Mainhand Weapon:
Executioner - Permanently enchant a Melee Weapon to occasionally ignore 840 of your enemy’s armor. Requires a level 60 or higher item.
or
Mongoose - Permanently enchant a Melee Weapon to occasionally increase Agility by 120 and attack speed slightly.
(situationally)
This is somewhat of a subject of debate. The safe answer is going double mongoose. Executioner does become superior to mongoose as a mainhand enchant deep into endgame raiding (Black Temple, Sunwell), especially for rogues with a lot of armor penetration. It also scales better with gear. It’s important to remember that both are extremely comparable. Mutilate should always use double mongoose.
OH Weapon: Enchant Weapon:
Mongoose
Head Enchant:
Glyph of Ferocity - 34 attack power, 16 hit rating
*Requires revered with Cenarion Expedition
Shoulder Enchant:
Greater Inscription of Vengeance (Aldor exalted) - 30 attack power, 10 critical strike rating
Greater Inscription of the Blade (Scryer exalted) - 20 attack power, 15 critical strike rating
Might of the Scourge (Naxxramas) - 26 attack power, 14 critical strike rating
Might of the scourge is superior to all other enchants if one has access to it.
Back Enchant:
Enchant Cloak - Greater Agility - 12 agility
Chest Enchant:
Enchant Chest - Exceptional Stats - +6 to all stats
Wrist Enchant:
Enchant Bracer - Assualt - 24 attack power
Hand Enchant:
Enchant Gloves - Superior Agility - 15 agility
Leg Enchant:
Nethercobra Leg Armor - 50 attack power, 12 critical strike rating
Boot Enchant:
Enchant Boots - Dexterity - 12 agility
Ring Enchant:
Enchant Ring - Stats - +4 to all stats
Enchant Ring - Striking (superior for daggers) - +2 physical damage
These enchants are available only to enchanters.
And last, but not least, please if you say +Rep, don't forget to actually give it, i am trying to work out my contributor status.