PH:
Alignment: This is the first thing I went to, given the controversy that's been swirling around it. First off: IT IS NOT A LINEAR SYSTEM--at least, no more than the old 3x3 grid. The alignments are listed in this order: Good, Lawful Good, Evil, Chaotic Evil, Unaligned. The definitions for Lawful Good and Chaotic Evil are very much what we are familiar with, and Good and Evil are similar to Neutral Good and Neutral Evil. The difference between Good and Lawful Good is that LG characters tend to think more about order and social structure, and while they recognize that authority figures can be corrupt and laws can be evil, they prefer to work within the system. Good characters can work with authority, but recognize that power tends to corrupt. The two alignments get along pretty well, but good characters think lawful good characters think too much about order and not enough about helping people. Evil characters want to do whatever they have to in order to get ahead (egoístas), while chaotic evils just do what they want regardless of who it hurts (sociopatas). The two evil alignments share a distaste for good, but don't generally get along that well.
There's also a sidebar on "Alignment vs. Personality". I didn't read it, but it's good to see it called out front and center.
Also, divine alignments, combining some information from the PH and DMG: Bahamut and Moradin are the only Lawful Good deities. Gruumsh, Lolth, and Tharizdun are Chaotic Evil. Correlon is, strikingly, Unaligned; the rest fall where you'd expect them, it seems.
MM:
The elder green dragon's mind poison is scary. Two failed saves, and not only can't you attack the dragon, you can't break out of it until a Remove Affliction ritual is used.
A note for the yugoloth fans: mezzodemons are "also known as mezzoloths", are more concerned with wealth than destruction, and are willing to retreat when a fight goes against them.
Lycanthropes have undergone some changes. There are only two of them in the MM--wererat and werewolf--and lycanthropy is no longer contagious. They do carry diseases that appear to have somewhat similar effects, though; the werewolf's moon fever can turn you into a bloodthirsty maniac. Diseases appear to function on some sort of condition track, where you move back and forth between 'cured' (at which point you stop moving) and several intermediate states before an end state, such as 'you attack the nearest creature' for moon fever. Still, given how important infective lycanthropy is to Eberron's backstory as I understand it, I wonder how they'll play that in 4E. (Licantropia é hereditária.)
Vampires are no longer repelled by garlic or unable to cross running water. (Granted, for those of us using Van Richten's Guide to Vampires, they've been able to cross running water for over seventeen years . . . ) The art's recycled from the 3.5E MM, so yes, the example vampire lord is using a spiked chain. There's also a ritual for vampire creation by vampire lords--it involves an exchange of blood, killing and burying the victim, and a prayer to Orcus.
Speaking of Orcus, he gets four pages in the MM. One of those pages is a reproduction of the cover art, but the other three give a writeup for him, his aspect, and his cultists. The Big Goat-Pig himself looks to be nasty--1,545 HP, anyone dead in his aura spontaneously animates as an abyssal ghoul myrmidion, and anyone slain by the Wand who's still dead at the state of his next turn revives as a dread wraith.
DMG:
Evil gods: Yes, they're here. The 'plus one' is Tharizdun, who is specifically noted as not mentioned in the PH or MM because of his obscurity in the default D&D world. Tiamat is enjoying her new role as a goddess of greed as well as evil dragons. Torog, who's been an enigma so far, is revealed as the patron of the Underdark, jailers, and (I believe) torturers. Lolth is specifically identified as a god and not a demon, even though she's called the Demon Queen of Spiders.
There's also a note on evil cleric powers--the powers in the PH, they admit, were designed primarily for Good or Lawful Good clerics and thus may be too 'shiny' for clerics of Evil or Chaotic Evil patrons. They suggest changing the radiant damage to necrotic damage, or just changing the special effects.
Artifacts: Well.
Well, well, well.
There are only four artifacts in the DMG--the Axe of the Dwarvish Lords, the Invulnerable Coat of Arnd, and, of course, the Eye and the Hand of Vecna. But they probably didn't have room for more, because the new system for using artifacts requires a fair chunk of space (one to one and a half pages) for each one.
This is a very interesting-looking blend of old school--the personality clash with artifacts in 2E (and probably 1E--I don't own the 1E DMG)--and new school--the affiliation system from the PH2. Artifacts have a set of basic powers, but characters also have a Concordance score with each artifact, based on their qualities or actions. The score's a twenty-point scale that breaks down into five tiers, IIRC (20-16, 15-11, 10-6, 5-1, 0). Characters with the ability to use arcane spells or who betray others, for instance, receive improved concordance with the Eye of Vecna. Improve the Concordance score, and you open up more powers; decrease it, and not only do you lose powers, but the artifact itself can turn against you. A character whose Concordance with the Eye of Vecna drops below 5, for instance, starts receiving horrifying visions from the Eye.
Each artifact also has a "Moving On" section; I'm not sure if that's triggered when the artifact's goal is completed, or/and the concordance drops to 0. The Axe of the Dwarvish Lords 'needs to be elsewhere', while the Vecna artifacts consume their wielder, body and soul. Nice touch for characters who choose to dabble in the dark side.
