Undead make great dungeon fodder; they are easy to justify in the dungeon setting, and there are lots of low-level choices to work with. While a lot are unintelligent, even the smart ones tend to be evil so as an added plus you do not have to feel guilty for hacking them apart (though you still might for the looting part).
The only bone I have to pick with the skeleton is its Charisma score (though Intelligence could stand to take a dive, too). The article states that since it lacks any sense of self, it has a Charisma of 3. This is the lowest that an actual character can roll, and while there are a variety of interpretations the lack of any sense of self is not one of them. I would drop it down to 1, the same as it was in 3rd Edition.
Zombies get a clean break on this one. Though I enjoyed the Zombie Weakness trait from 4th Edition (they die on a crit, which is representative of a "head shot"), it does not make sense given that they are not alive.
One thing that is absent from the article is the default alignment of skeletons and zombies (as well as other mindless undead). In 2nd Edition they were just slated as neutral, which made sense given the inability to make an informed choice. I mean, is a golem commanded to kill everyone evil? Is an animated object? 3rd Edition changed this up by making them neutral evil despite a complete lack of intelligence, which caused several extensive threads on the WotC forums back in the day (though 4th Edition brought them back to unaligned).
I remember in 2nd and 3rd Edition how you would turn into a ghoul if you were killed by one. This was changed in Revised, so that they would instead infect you with a disease (ghoul fever), meaning that survivors of ghoul attacks might die anyway and transform into one (which was more inline with zombie movies). This made more sense to me, as ghoul victims were more than likely going to be eaten anyway.
Checking past editions I could not find anything mentioning how the original Dungeons & Dragons ghouls came to be, and while ghouls begetting ghouls is a classic, I find the idea of ghouls-as-cursed-humans to be more interesting (and fresh). I would even go so far as to suggest some ghouls being able to take the shape of the last person they ate (as in both Arabian folklore and The Dresden Files).
Conceptually the vampire hits all the right points for me, which given their treatment in recent editions was to be expected. Hopefully I will get to run Expedition to Castle Ravenloft this edition. Eh, maybe I will convert it when we the level cap hits 10.