Dreadmist Raiment (warlock)
The Dreamist Raiment set is for warlocks. The most difficult piece to obtain in vanilla was probably the Dreadmist Mantle. Jandice Barov was a pain to clear to and a pain to kill in the early days, largely due to her annoying habit of splitting into a million clones. These days, she's pretty easy to knock over solo at level 80.
Battlegear of Valor (warrior)
The Valor set is primarily found in Stratholme, but other pieces can be found in other areas. In vanilla, probably the most difficult piece of this set to obtain was the boots, because they dropped from a boss that was pretty optional unless people were on the quest to kill him.
Beaststalker Armor (hunter)
The Beaststalker set was the first in a long set of "stalker" armor for hunters. The hardest piece for hunters to obtain was usually the gloves, because War Master Voone was located in a fairly out-of-the-way area in Lower Blackrock Spire.
The Elements (shaman)
Prior to The Burning Crusade
, only the Horde had to worry about the location of the Elements set, as they were the only faction that had shaman. Luckily for shaman, most of their set pieces were on bosses that people wanted to kill anyway.
Lightforge Armor (paladin)
Again, prior to The Burning Crusade
, only one faction had to worry about this set. Alliance was the home of the paladin, and thankfully, the paladins didn't have to worry overly much about any of their set pieces, as they all dropped off of bosses that needed to be killed to move on in the instances.
Magister's Regalia (mage)
Poor, poor mages. Once upon a time, the boots for the Magister's set dropped from Postmaster Malown
, a boss that pretty much nobody ever wanted to kill
. This was because it took a crazy amount of time to get him to spawn -- so most mages had to go without their boots until the drop was changed to the Hearthsinger
, who was much easier to find and destroy.
Shadowcraft Armor (rogue)
As with the hunters, rogues had a hard time with a piece of their set because of its out-of-the-way location. In this case, it was the gloves that dropped from a boss in a remote location in Lower Blackrock Spire.
Wildheart Raiment (druid)
Druids luckily had a fairly easy time with their sets in vanilla, because most bosses that dropped their set pieces were also objects for quests in the various dungeons.
Vestments of the Devout (priest)
And then we have the priests. Much like mages, priest had a terrible time trying to get their shoulder armor due to their dropping from a boss that could only be spawned by doing an event. Nobody ever wanted to do the event.
The Postmaster (cloth, all classes)
This set is a little ... unique. It was the only blue set other than the class sets, and it didn't have a class specification. All pieces dropped in Stratholme from Postmaster Malown, who I mentioned earlier. The reason this set is so hard to obtain is the sheer amount of annoyance in getting Malown to spawn. First, you have to travel to live side Stratholme and kill the Stratholme Courier
, who will drop keys to various mailboxes throughout the area. Next, you have to travel to the mailboxes and open them, which will spawn several elite mobs. You must do this three times; when you open the third mailbox, Postmaster Malown will spawn. Kill him, and he will drop a piece of the Postmaster set. While most of the set pieces drop relatively frequently, the Postmaster's Band only has about a 5 percent drop rate, so you have to keep resetting the instance, killing the Courier, killing Malown, and praying. The completed set looks snazzy and grants a lot of set bonuses; if you have the full five pieces, you get a 5 percent boost to run speed, presumably to help you deliver the mail that much faster. Be warned, it takes a crazy amount of time to farm this set -- so unless you're a serious set collector, you can probably skip it.
Although it hasn't been confirmed, the bosses that drop these various set pieces are changing, as well as the instances they live in currently, so these set pieces may simply disappear upon Cataclysm's
launch. If you're looking for unique gear that may prove to be even more unique in the years to come, be sure to pick up these old armor sets before they vanish.