Best overall: Deathchill Cloak, a Tailoring BoE.
Best drop: Ancient Dragon Spirit Cape, from the cache of Eregos in heroic Oculus.
Best quest piece: Bloodbane's Fall, from the quest The Fate of Bloodbane in Icecrown.
Best faction piece: Dark Soldier Cape, available at honored with the Ebon Blade. If you don't need the +hit on this piece, you may want to substitute Shroud of Dedicated Research (honored, Kirin Tor), but the stats are otherwise better on Dark Soldier.
Enchant: Enchant Cloak -- Greater Speed. Some people have suggested Enchant Cloak -- Wisdom but frankly it's still way too expensive for what you get.
Best overall: Heroes' Dreamwalker Vestments, available for 80 emblems of heroism.
Best drop: Water-Drenched Robe from Ichoron in heroic Violet Hold. If you're hit-capped or just having problems getting Ichoron in VH runs, try Insect Vestments off Anub'arak in heroic Azjol-Nerub.
Best quest piece: Robes of Lightning, from the quest Whatever It Takes in Halls of Lightning.
Best faction piece: Robes of Crackling Flame, available at exalted with the Kirin Tor. This is definitely not designed with Balance in mind, as too many of its item points are given to mp5, but it's OK in a pinch.
Runner-up: Ebonweave Robe, a Tailoring BoE.
Enchant: Enchant Chest -- Powerful Stats.
Best drop: Azure Cloth Bindings from Cyanigosa in heroic Violet Hold, or Plague-Infected Bracers from the Dark Runed Chest in heroic Culling of Stratholme.
Best quest piece: Wristguard of the Bone Witch, from the quest Not-So-Honorable Combat in Icecrown.
Best faction piece: Ancestral Sinew Wristguards, available at revered with the Kirin Tor, or Wound-Binder's Wristguards, available at revered with the Ebon Blade, depending on how you socket Ancestral Sinew. Wound-Binder's are otherwise superior.
Runner-up: Black Duskweave Wristwraps, a Tailoring BoE.
Enchant: Enchant Bracers -- Superior Spellpower, but it's pretty damn expensive at the moment. If you're having cashflow problems, take Enchant Bracers -- Greater Spellpower. Leatherworkers will want to use Fur Lining -- Spell Power.
Best overall: Heroes' Dreamwalker Gloves, available for 60 emblems of heroism.
Best drop: Gloves of Glistening Runes, from Keristrasza in heroic Nexus. With that said, Gray Matter points out that there are no less than three potential glove drops in heroic Halls of Lightning that aren't too far off stats-wise, so if you get any of those you're probably fine.
Best quest piece: Gloves of the Servant, from the quest The Reckoning in Storm Peaks.
Best faction piece: Sterile Flesh-Handling Gloves, available at revered with the Ebon Blade.
Runner-up: Ebonweave Gloves, a Tailoring BoE.
Enchant: If you're having problems reaching the hit cap, Enchant Gloves -- Precision. Otherwise, Enchant Gloves -- Exceptional Spellpower.
Best overall: Plush Sash of Guzbah, available for 40 emblems of heroism. Vine Belt of the Woodland Dryad is also usable and available for 40 emblems of heroism, but unless you're already +hit-capped Plush Sash is better.
Best drop: Girdle of Bane from King Ymirjon in heroic Utgarde Pinnacle. Sash of Blood Removal from Gal'darah in heroic Gun'drak is fine if you're already hit-capped.
Best quest piece: Sly Mojo Sash from the quest Gal'darah Must Pay in Gun'drak, or Belt of the Never-Forgotten from the quest Light Within the Darkness in Icecrown.
Best faction piece: Belt of Dark Mending, available at exalted with the Ebon Blade, or Ghostflicker Waistband, available at exalted with the Kirin Tor. This will depend on how you socket Ghostflicker, and whether you're stressing +crit over +haste.
Runner-up: Sash of the Wizened Wyrm, available at honored with the Wyrmrest Accord, or Deep Frozen Cord, a Tailoring BoE.
Enchant: Not really an enchant as such, but you'll want an Eternal Belt Buckle.
Best overall: Leggings of the Winged Serpent, from the Prophet Tharon'ja in heroic Drak'tharon Keep.
Best drop: Woven Bracae Leggings, from Loken in heroic Halls of Lightning.
Best quest piece: Snowdrift Pantaloons from the quest The Iron Colossus in Storm Peaks. Interestingly, your next-best option is Leggings of Heightened Renewal from the same quest.
Best faction piece: Giant-Friend Kilt, available at revered with the Sons of Hodir.
Runner-up: Sorrowgrave's Breeches, from Svala Sorrowgrave in heroic Utgarde Pinnacle, or Black Duskweave Leggings, a Tailoring BoE.
Enchant: If you're hurting for stamina, slap on Sapphire Spellthread; otherwise you'll want Brilliant Spellthread.