The items listed below are suggestions for gear to grab on your way to heroics. The idea is to provide ways to get heroic geared without having to rely on instancing to obtain the gear. Most slots have an option for items obtained via questing, reputation vendors, crafted items, or Bind on Equip items. I hightly recommend instancing as much as possible on your way to tanking heroics, because honestly, unless you have tanking experience all the gear in the world is worth nothing. The majority of these items can be obtained after you hit level 77. A few of the quests involved require you to be able to fly in northrend.
Head Slot Items
Tempered Saronite Helm Crafted - Mats
Best Choice for maximum defense.
Helm of the Ley-Guardian 14% drop from Ley-Guardian Eregos in The Oculus (Normal Difficulty)
Best choice for maximum stamina and armor for non-engineers.
Armored Titanium Goggles From Engineering
Best choice for maximum stamina and armor for engineers. Also has a meta and red socket (+6 stamina bonus)
Neck Slot Items
Reinforced Titanium Neckguard From quest - The Admiral Revealed Requires Level 78.
Best choice for maximum defense (26 base + defense gem). Red Socket (+6 stamina bonus)
Betrayer's Choker From quest - Betrayal Requires Level 74.
Best choice for balancing stamina with defense and hit rating. Yellow Socket (+6 Stamina) makes it a great choice for adding defense gem.
Shoulder Slot Items
Tempered Saronite Shoulders Crafted - Mats
Best choice for Defense and has more stamina than similar BoE and quest items.
Crusader's Square Pauldrons 0.2-1.2% Zone Drop from Culling of Stratholme (Normal Difficulty)
Best choice for armor. While it does not have the stamina and defense of the Tempered Saronite Shoulders, it does have parry rating which could be useful if you can remain defense capped with this item equipped.
Back Slot Items
Cloak of Peaceful Resolutions Purchasable at honored Wyrmrest Accord reputation.
Best choice for stamina and defense. The level 78 requirement gives you plenty of time to grind wyrmrest reputation. I recommend finishing any Coldarra questlines mentioned in the link above, as well as any Dragonblight quests.
Cloak of tormented Skies Crafted - Mats
Great choice for improved armor. Also more easily attainable as it is crafted, if you wish to avoid reputation grinding or excessive questing.
Chest Slot Items
Battlechest of the Twilight Cult 28% drop from Jedoga Shadowseeker in Ahn'kahet: The Old Kingdom (Normal Difficulty)
I list this boss drop only because of its excellent stats and level 73 requirement. This piece can be used up until you can get into Utgarde Pinnacle and replace it.
Reanimated Armor 21% drop from Gortok Palehoof in Utgarde Pinnacle
Another boss drop listed because you will be running Utgarde Pinnacle for the Silver-Plated Battlechest anyway. You might hold onto this one not only because it has the best strength/stamina, but also includes some parry rating. Very useful if you can remain defense capped with this piece on.
Silver-Plated Battlechest From quest - Junk in My Trunk Requires Level 78.
Best choice for defense. Also has great armor and tons of stamina. Quest is easily completed in one run of Utgarde Pinnacle.
Wrist Slot Items
Tempered Saronite Bracers Crafted - Mats
Best choice for maximum defense. Lowest stamina.
Bracers of Reverence From quest A Wing and a Prayer Requires level 77.
Requires you to go into The Oculus and defeat Ley-Guardian Eregos. Aside from getting these middle-ground defense/stamina bracers you have a chance to grab the Helm of the Ley-Guardian.
Svala's Bloodied Shackles 23% drop from Svala Sorrowgrave in Utgarde Pinnacle
Utgarde Pinnacle to the rescue again. This piece is the best choice for maximum stamina, but has the lowest defense. What makes this piece also desireable is the dodge rating for when you can remain hit capped with this item on.
Hand Slot Items
Daunting Handguards Crafted - Mats
Best choice for maximum defense.
Gauntlets of Vigilance From quest The Reckoning Requires level 77.
Best choice for stamina and strength hands down. Yet another piece that is great to have when you can afford the loss of defense.
Waist Slot Items
Tempered Saronite Belt Crafted - Mats
Best choice for maximum defense.
Girdle of Obscuring 17% drop from Mage-Lord Urom in The Oculus
Best choice for stamina and strength. Also has parry rating if you can afford the loss of defense.
Legs Slot Items
Special Issue Legplates Purchaseable at honored Argent Crusade reputation.
Legs are a tough choice. I recommend these due to the red socket (+4 strength) and high stamina. They offer the lowest strength, but have hit rating which will help you get started in heroics.
Daunting Legplates Crafted - Mats
These really are an excellent choice being the best for defense and having a decent amount of stamina and strength.
Feet Slot Items
Tempered Saronite Boots Crafted - Mats
The only boots that don't have "shield block value". Perhaps better traction on your shoes helps you not get knocked down when using your shield? Either way these have decent stamina and strength while also edging out all other choices for defense.
Finger Slot Items
Solid Platinum Band From quest For Posterity Requires level 74.
One of two rings available via questing. While you're in Gundrak, be on the watch for Gal'darah's Signet which drops from Gal'darah.
Kurzel's Warband From quest Search and Rescue Requires level 72.
This quest obtained ring takes you into Drak'tharon Keep.
Trinket Slot Items
Seal of the Pantheon 19% drop from Loken in Halls of Lightning (Normal Difficulty)
The only trinket with defense on it. Useful in swapping out lower defense items in other slots.
Weapon Slot Items
De-Raged Waraxe From quest The Champion of Anguish Requires level 75.
This axe really is the best choice for your weapon. It has stamina, strength, hit, and crit rating. If you add Rune of the Stoneskin Gargoyle to it you'll have 25 defense also.
Axe of Bloodstained Ice From quest Cradle of the Frostbrood Requires level 77.
The only reason I have listed this item is in case you're in a jam and need to up your defense rating. You could even add the Rune of Stoneskin Gargoyle to it if you're really desperate.