Bashiok went on to explain just what monsters this included. The Diablo III team is currently using certain terms and categories to help decide which monsters get what treatment.
Official Blizzard Quote:
As far as I know it right now the terms we're using and what they mean:
Champions - small packs of tougher mobs that share affixes, increased health, damage, harder, etc.
Rares - affix-laden enemy, much tougher, comes with a group of minions that inherit their affixes and bonuses
Uniques - Unique boss monsters. Unique name/art/skills/lairs and are usually a part of the story/goal of a quest, if not the actual end-boss of an act. The Skeleton King and the Siegebreaker would both be uniques
So, following very closely to Diablo II's rankings for enemies, Diablo III will have many varied encounters with the monsters that are inhabiting Sanctuary. We all remember the random group of champions that would rush up to our hero ,especially those ghostly physical immune while playing a Barbarian. Rares also added a fun change of pace with their randomly selected attributes that would make them especially tough to beat compared to their normal counterparts. Uniques added perhaps the biggest change in combat other than bosses. Memorable foes like Radament, Blood Raven, and The Ancients stopped us from our usually thoughtless hacking and forced us to think and strategize on how to kill these monsters.
With Diablo III, we have seen a few of these unique monsters that they have planned. The Siegebreaker Assault Beast and the return of the Skeleton King Leoric were both show cased as the finale of the demos that were playable. Impressive battles that rivaled, if not, were better than the boss fights of Diablo II. Unique death mechanics of the Siegebreaker biting of the head of the Barbarian and throwing his lifeless corpse to the ground is an image many of us get excited about. The dynamic lair of the Skeleton King exemplified just how much more interesting these battles will be as oppose to the boring room when fighting Duriel. These impressive battels show just how much better Diablo III will be then the already legendary Diablo II. Even the epic battle of the Barbarian against the Thousand Pounder is only considered to be a rare monster.
As Bashiok mentioned in his post, regular monsters have a chance of dropping a small health globe after killing them. Champions will have a chance of dropping a bigger health globe once while they are alive and then a chance after killing them. Rares, like the Thousand Pounder have a chance of dropping even bigger health globes every quarter of their life and once again upon killing them. Unique monsters may act the same as rares but the plan is to have them have other ways and chances for the player to refill their HP.
Official Blizzard Quote:
Uniques/Bosses... ? Maybe! But their health replenishing mechanics (among other things) have a better chance of being a bit more creative since their lairs are specifically designed for them.
One example of how this will work is the minions of King Leoric that attack you at the same time as fighting himself. Forcing players to fight off these smaller monsters to get health globes is one way of adding chances and tactics to the harder fights. Destructible environments are sure to play a role as well as additional sources for much needed life. Who knows what other imaginable uniques and interesting lairs the development team will create to challenge us and memorable battles. Perhaps monster concepts like these will be found in the game. Monsters that are more then just higher HP and defense and cause us to think on how we are going to defeat them. Lairs much more interesting and interactive will allow us to move around and focus on more than just the one monster we are fighting.
Perhaps the most interesting thing we can take and think about from all of this information is the idea of what the actual boss fights will be like. While we don't know exactly who these bosses are, we can only presume that these battles are going to be even more epic than the unique battles. Just how amazing they are is up to anybody's speculation.