Death Knights have it pretty good. Old school players will remember the pain of collecting our dungeon sets, such as the Shaman's The Elements or the Paladin's Lightforge Armor. These weren't class-specific armor sets, but for a long time they certainly represented the best of how some classes looked. Completing these armor sets were a real pain, with key pieces dropping off the end bosses of what were then the hardest dungeons in the game. Head pieces dropped off Darkmaster Gandling in Scholomance, leg armor dropped from Baron Rivendare in Stratholme, and the chestpiece from General Drakkisath in Upper Blackrock Spire.
In Wrath of the Lich King, Death Knights won't be hoping for drops from bosses. They won't need to. If Wrath breaks as planned, Death Knights will be getting upgrades in every slot before they even reach Level 60 -- through quests. This includes a full complement of absolutely badass armor that isn't really an Item Set but a visually matched assortment of blue (literally and item level-wise) gear. I think I'll dub it the Deathplate Armor. Check out the gallery for a look at all the quest swag Death Knights get through questing.
Gallery: Death Knight Blue Rewards