It's not a new thread, but it was stickied and has gathered many positive replies. I'm talking about the DK preraid Itemization for Tanks: a gear guide, written by Ragnarok on the official Blizzard forums. I'm going to summarize what's been said there. The goal is to get enough Defense Rating on your gear to become uncritable. (For the DK this means you need 540 defense skill, or a total of 689 defense rating.) Without sacrificing that, get as much stamina and strength in the gear as you can. Here are the items to achieve this as suggested by Ragnarok:
Head: Ground Tremor Helm, Drops in Gundrak(H).
--> enchant with: Arcanum of the Stalwart Protector (Argent Crusade-Revered)
Neck: Chained Military Gorget, 25 Emblems of Heroism in Dalaran
Shoulder: Iron Dwarf Smith Pauldrons, Drops in Halls of Lightning(H)
-->enchant with: Greater Inscription of the Pinnacle (Sons of Hodir - Exalted)
Back: Cloak of Peaceful Resolutions, 20g from Wyrmrest Accord at Honored.
-->enchant with: Enchant Cloak - Titanweave
Chest: Breastplate of the Solemn Council, 52g from Wyrmrest Accord at Revered.
-->enchant with: Enchant Chest - Greater Defense
Wrist: Bindings of Dark Will, Drops in CoT: Stratholme(H)
-->enchant with: Enchant Bracer - Fortitude
Hands: Gauntlets of Vigilance, Reward from The Reckoning in Storm Peaks
-->enchant with: Enchant Gloves - Armsman
Waist: Waistguard of the Risen Knight, BOE Drop in Drak'Tharon Keep(N)
-->Add a belt buckle, throw in a +16 STR (or something else if you like).
Legs: Daunting Legplates, Crafted by Blacksmithing (sells for 30g on my server)
-->enchant with: Frosthide Leg Armor
Feet: Sabatons of Draconic Vigor, 37g from Wyrmrest Accord at Revered
-->enchant with: Enchant Boots - Greater Fortitude
Ring 1: Gal'darah's Signet, Drops in Gundrak(N)
Ring 2: Dragonflight Great-Ring, Drops in Nexus(N)
Trinket 1: Essence of Gossamer, Drops in Azjol-Nerub(N)
Trinket 2: Seal of the Pantheon, Drops in Halls of Lightning(N)
Weapon: Titansteel Destroyer, Crafted by Blacksmithing.
-->(as of next patch) Put the +25 Defense runeforge on.
Relic: Sigil of Haunted Dreams, 15 Emblem of Heroism in Dalaran
So now I have something to shoot for, I'll have a suggestion for an instance to go when someone asks "where do we want to go now?" Will keep this updated with Failsauce's progress towards becoming uncritable.