Best overall: Sharp-Barbed Leather Belt, off Ingvar the Plunderer in heroic Utgarde Keep. Trollwoven Girdle is very close to Sharp-Barbed stats-wise and easy to get made. Jorach's Crocolisk-Skin Belt is also pretty close but not, in my opinion, worth shelling out 40 emblems if you can get Trollwoven. These three pieces are way better than anything else you can put in this slot barring the Deadly Gladiator's Belt of Triumph, so at the very least count on having Trollwoven made if you can't get Sharp-Barbed to drop.
Best drop: Batrider's Cord off Trollgore in heroic Drak'tharon Keep.
Best quest piece: Honestly, there's not much here. The best I could find was Strange Voodoo Belt, from the quest Gal'darah Must Pay in Gun'drak.
Best faction piece: Glitterscale Wrap, available at revered with the Oracles.
Runner-up: Yet another Oculus BoE shows up in this slot, the Ley-Whelphide Belt. Other BoE's include Eviscerator's Waistguard, a Leatherworking BoE, and Treasure Seeker's Belt, a heroic Azjol-Nerub BoE, although Treasure Seeker's agility is a little low for my taste.
Enchant: Not an enchant as such, but you'll want to add another socket with an Eternal Belt Buckle.
Best overall: Savage Gladiator's Dragonhide Legguards, available for 60,000 honor or 45 emblems of heroism.
Best drop: Legguards of Swarming Attacks off Amanitar in heroic Ahn'kahet, or Ravenous Leggings of the Furbolg off Gortok Palehoof in heroic Utgarde Pinnacle.
Best quest piece: As with the belt slot, there's not much here, but Tattooed Deerskin Leggings from the fairly early quest Containment in Violet Hold are the best you'll get from questing.
Best faction piece: Mind-Expanding Leggings, available at revered with the Kirin Tor. If you don't have the necessary rep for these but the Frenzyheart like you just fine, try the Azure Strappy Pants, available at revered with them.
Runner-up: Gored Hide Legguards off Gal'darah in heroic Gun'drak. Gored Hide, Mind-Expanding Leggings, Legguards of Swarming Attacks, and Ravenous Leggings are pretty close to each other once socketed and enchanted, just FYI. If your loot luck is even worse than mine and all of the game's factions hate you, fall back on Eviscerator's Legguards, a Leatherworking BoE, or Chain Gang Legguards, a BoE trash drop from heroic Violet Hold.
Enchant: Frosthide Leg Armor.
Best overall: Titan-forged Boots of Triumph, available for 15 Wintergrasp marks. /sigh.
Best drop: Slag Footguards, off Volkhan in heroic Halls of Lightning. Boots of the Whirling Mist off Sjonnir in heroic Halls of Stone are fairly similar but unfortunately lack a socket. Gorloc Muddy Footwraps off Eck the Ferocious in heroic Gun'drak are also usable, though not quite as good as Slag.
Best quest piece: Rhino Hide Kneeboots, from the quest One of a Kind in Gun'drak.
Best faction piece: Boots of the Neverending Path, available at exalted with the Argent Crusade. It's actually relatively tough to get +hit on bear-oriented gear and this has a ton of it.
Runner-up: Boots of Captain Ellis, available for 40 emblems.
Enchant: Most raiding bears swear by Tuskarr's Vitality, but you may want to use Enchant Boots - Superior Agility, Enchant Boots - Greater Fortitude, or Enchant Boots - Icewalker depending on your current gear set.
Best overall: Keystone Great-Ring, from the Prophet Tharon'ja in heroic Drak'tharon Keep. This is really an excellent piece; try to get this if at all possible.
Best drop: Band of Torture, off Drakos the Interrogator in heroic Oculus, or Nerubian Shield Ring, off Elder Nadox in heroic Ahn'kahet.
Best quest piece: Iceforged Battle Ring, from the quest Forging the Keystone in Storm Peaks.
Best faction piece: n/a.
Runner-up: Titanium Earthguard Ring, a Jewelcrafting BoE, or Ring of Earthen Might, another Jewelcrafting BoE.
Enchant: If you're an Enchanter, you'll want Enchant Ring - Stamina.
Best overall: Hands down it's Darkmoon Card: Greatness. You may very well go your entire span of time in Wrath without ever replacing this trinket for your avoidance set. Slit throats, break hearts, bribe everyone in sight, do whatever you have to do, but GET IT.
Best drop: Essence of Gossamer, off Hadronox in heroic Azjol-Nerub. Offering of Sacrifice, off Gal'darah in heroic Gun'drak, is no longer as good as it once was primarily because we don't get bonus AC from trinkets anymore and the proc isn't anywhere near as good as what you'd get on the Naxx-25 Defender's Code. Numbers-wise it's even inferior to Badge of Tenacity once the proc is taken into consideration, which is somewhat sad. Probably the piece of gear most affected by the 3.0.8 changes.
Best quest piece: Actually, I'm kind of stumped here. If you have a Badge of Tenacity and a Commendation of Kael'thas or Shard of Contempt coming into Wrath, you could theoretically go all the way to heroics at 80 without replacing either one. Thoughts?
Best faction piece: The only things available in this slot are the Oracle Talisman of Ablution and the Frenzyheart Insignia of Fury. Not really great, but I'm somewhat curious to see how the Oracle trinket will work in conjunction with the upcoming Savage Defense ability.
Runner-up: Valor Medal of the First War, available for 40 emblems of heroism, is excellent, and should probably be purchased no matter what for your avoidance set. Jewelcrafters will want to have a Figurine - Monarch Crab and a Figurine - Ruby Hare prepped; Alchemists will want an Indestructible Alchemist's Stone for their stamina set.
Before anyone else asks me, the best of the "new" tanking weapons now available to Druids is Inevitable Defeat, a rare BoP trash drop in Naxx-25, and the next best is Black Ice, off Malygos-10. However, before raids most of your best options are still going to be pieces that were Druid-specific pre-3.0.8 (and the best tanking weapon in the game remains Origin of Nightmares, which steadfastly refuses to drop for me in much the same manner that Pillar of Ferocity did).
Best overall: Even with the changes to AC from weapons and the new availability of polearms, you'll still want an Enraged Feral Staff off Ingvar the Plunderer in heroic Utgarde Keep.
Best drop: Staff of Trickery, off Cyanigosa in heroic Violet Hold. Your next option is Witch Doctor's Wildstaff off Slad'ran in normal Gun'drak.
Best quest piece: Eh. You'll find plenty of usable pieces while questing, but they all pale in comparison to what you can get in heroics.
Best faction piece: Stave of Shrouded Mysteries, available at revered with the Kirin Tor, or -- I cannot believe I am writing this -- Whale-Stick Harpoon, available at revered with the Kalu'ak.
Runner-up: Bloodwood Greatstaff is a rare world-drop BoE, but it suffers pretty badly from a lack of stats aside from 700 armor. The Savage and Hateful Gladiator's staves are very good (Hateful clocks in above Staff of Trickery but below Enraged Feral), and the Deadly Gladiator's Staff is now the second-best tanking staff in the game (much to my despair).
Enchant: Enchant Weapon - Mongoose is the way to go. Some still prefer the reliability of Enchant 2H Weapon - Major Agility, however, but both are going to become even less useful as time goes on and bear dodge approaches more diminishing returns on agility. I agree that axing Titanguard was ultimately a good idea, but it does kind of suck that we don't yet have a Wrath-level tanking enchant or idol.