Depends on your tastes. IMO My OP looks pretty good for it!
PS: I never noticed my thread from 2 years ago became a sticky
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Two years later, here's my new (and current) mog!
Want it for yourself? It's not that hard to get:
Helmet: Heroic T11 (BWD/BoT/To4W) [Drops from Nefarian, though Power Generator Hood from Heroic Omnitron is a copy/paste alternative, as well as the alternative alternative from Sinestra]
Shoulders: Normal Warlock T15 (ToT) [The ones I'm using are Fissure-Split Shoulderwraps from Jin'rohk] (These shoulders used to be Heroic T11, but once I saw this pair, I felt it matched the helm better)
Chest: Normal T12 (FL) [Just buy it from the vendor!]
Gloves: Heroic T11 [No alternative, so you need to defeat Heroic Magmaw for the token or Heroic Al'Akir for the Essence]
Belt: "Normal T12" [You need to be honored with Avengers of Hyjal for this one as it's a reputation item. Do some Firelands or AoH dailies to nab it]
Boots: Heroic T11 [Only drops from Chimaeron, though the boots don't matter too much. The N T12 boots work just as fine]
Pants: Lol who am I kidding? You can't see my pants! I could be wearing nothing for all you know
(PS: Ignore Creeto and Chipshandon in the background. They're pieces of shit.)
[Randy/Bryan, if you're reading this, I love you guys :3]