So, you want gear? Emblems, my son. Emblems.
For starters, you should have already been tanking stuff. Even if you didn't really want to level as prot (some folks really like the prot leveling experience; others do not), if you intend to tank at level 80, you have no excuse; you should be tanking from at least 70 on. Not only will using the LFD tool once a day net you a shiny pair of Emblems of Triumph that you can spend as soon as you hit 80, but it's the fastest, easiest way to learn what you're intending to do once you're at max level. Tanking, like any skill, benefits from actively practicing, and 5-mans are solid places to get that practice. Plus, gear drops in them, and for a leveling prot, making sure you're uncrittable at 80 (535 defense for heroic five mans, 540 defense for raids) is crucial. Trust me, once you start queuing at 80, you are going to find your gear under a microscope by people who think they know everything there is to know about tanking because they rolled a DK and got him to 72.
First off, of course, you can buy the entirety of the ilevel 232 version of the tier 9 tanking armor (Horde version). My advice would be to deliberately not buy the hat or shoulder piece, however, and just get four pieces for the set bonus. The ilevel 245 tanking hat and shoulders (Alliance versions) are pretty nice and can last you a way into ICC-10 if that's where you're intending to go, and if you don't raid or intend to raid at all, they could last you even longer. I really like the expertise on the hat since it can help ease the transition as you replace gear. (And frankly, the block value on the T9 hat is underwhelming ever since they neutered block value for our Shield Slams)
In addition to set pieces, there are accessories to consider from Emblems of Triumph, namely a trinket, ring and throwing weapon. Both the trinket and ring have bonus armor, making them very attractive, while the throwing weapon is just well itemized with a nice dollop of hit to help with threat as well as dodge and defense for avoidance. The Glyph of Indomitability is well itemized enough to be held onto for any fight where you're certain you'll be taking lots of physical damage.
To save time, we're going to just cover the gear you can pick up in normal and heroic Trial of the Champion and the ICC 5-mans. There are certainly other ilevel 200 epic drops from the various heroics that launched with Wrath, but you'll do those dungeons as part of LFD to maximize your emblems per day, so just be on the lookout for any tanking epics that drop. Usually no one else will want them, anyway.
We covered Trial of the Champion loot in two big posts. We'll distill down the tanking drops of interest here: The Peacekeeper Blade. The Black Heart. The Mark of the Relentless. Boots of Heartfelt Repentance. Girdle of the Pallid Knight. Legguards of Abandoned Fealty. Mercy's Hold. Helm of the Crestfallen Challenger. Regal Aurous Shoulderplates. The Warlord's Depravity.
Please don't make the mistake of passing on these because they're ilevel 200/219. The ring and trinket in particular are among the best you'll be able to get before raiding, and even the rest of these drops can be of use to you if you don't have comparable or better in those slots. Sure, you'll most likely replace a lot of them with emblem purchases, but these drops can help you get to those emblems. Even if it's a minimal upgrade, take it. Even if you know you'll replace it in a week, if you'll use it now, take it.
Covering the ICC 5-mans, Forge of Souls has the Legplates of Frozen Granite, Lucky Old Sun and Sollerets of Suffering on normal and Black Spire Sabatons on heroic. The Pit of Saron yields Scourgelord's Frigid Chestplate and the Titanium Links of Lore on normal and the Icebound Bronze Cuirass, Ick's Rotting Thumb, Rimefang's Claw and Shoulderplates of Frozen Blood on heroic. (Rimefang's Claw in particular is well worth getting -- most likely the best tanking weapon for most warriors outside of ICC-10.) Meanwhile, normal Halls of Reflection gives one a chance at the Splintered Door of the Citadel (a very nice shield), the Eerie Runeblade Polisher for a cloak and the Crystalline Citadel Gauntlets. Heroic mode, meanwhile, offers up Falric's Wrist Chopper (orcs may prefer it to the Rimefang's), the Fossilized Amniote Choker and the Second Helm of the Executioner. As you can see, heroic ICC-5 drops are on par with the tier 9 you'll most likely be purchasing alongside them, so they're worth pursuing.
A-tisket, a-tasket, a crafter's craft set (and instance BoEs, too!)
What about crafted items? You can make or find quite a few on the AH. First off, the easiest to acquire. The Titansteel Shield Wall, Tempered Titansteel Treads and Tempered Titansteel Helm will most certainly be among the first things you replace, but they have decent stats and are pretty easy to make. (It should be pointed out that the Tempered Titansteel Helm has a blue socket, a meta socket and very high stamina, making it fairly strong for its ilevel.)
The Indestructable Plate Girdle is fairly strong with two sockets (which, combined with a third, leaves lots of room for stamina gems) but, as an Ulduar recipe, is slightly harder to make. (Tip: You can convert frozen orbs to various orbs used in crafting.) The Trial of the Crusader recipe Saronite Swordbreakers and Breastplate of the White Knight are still fairly common on most AHs. And if you have money to burn, the Boots of Kingly Upheaval and Pillars of Might are available. The extremely high armor value on the Pillars makes them probably the best tanking legs in the game right now for a warrior, if you can make up the loss of defense (which you should be able to fairly easily).
Since the weekly dungeon raid quest tends to send folks to older content from time to time, the following BoE drops from 10- and 25-man raids are worth looking out for. Signet of the Accord (Sarth-10), Band of the Traitor King (Anub'arak-25), Harbinger's Bone Band (ICC-10/25 and ICC-10/25 weekly raid quest sack drop), Signet of the Earthshaker (XT-002-25), Northern Barrier (Hodir-25) and Rowan's Rifle of Silver Bullets (ICC-10/25 and weekly raid quest sack drop).
This should be enough for your new level 80 warrior to start working on. Next week, either the delayed 21/40 post, or Arms warriors at 80.
Check out more strategies, tips and leveling guides for warriors in Matthew Rossi's weekly class column, The Care and Feeding of Warriors.