Quad Deathblow X44 Goggles

For rogues, these are very slightly better than the Slayer's helm (disreguarding the tier 6 set bonuses) and will be a very popular piece in the arena as well as in PvE.

Stat comaprison Agi/Stam/Hit/Crit/AP.

Slayers - 45/55/19/28/92

X44 - 65/47/24/0/104

As you can see here, X44 comes out ahead, with +20agi, +5 hit and 12 AP traded off against -28 crit.
The recipie appears to be a BoE drop from trash mobs in the sunwell, and the mats are very cheap.

These drop from trash mobs on the Sunwell Plateau and are tradeable at the AH. They are not BoP.

Likely to be priced well over 1500g on PvP servers.

Quad Deathblow X44 Goggles on PTR

Leather
Head
326 Armor

+61 Agility
+47 Stamina
*Meta Socket
*Blue Socket
**Socket Bonus: +4 Agility
Requires LvL 70
Requires Engineering 350
Equip: Improves hit rating by 24.
Equip: Increases attack power by 104.
Equip: Shows the location of all nearby gas clouds on the minimap.
Equip: Slightly increases your stealth detection.
Use: Allows you to look far into the distance.