Donovan Morningfire said:
Harry: Definitely Neutral Good. He's out to do the right thing for the greater good, rules be damned.
Hermione: I'd say she starts out Lawful Neutral and by series end she's Lawful Good. Just remember that Lawful Good doesn't mean upholding rules you know are wrong, evil, or spiteful.
The Weasleys: Ron is Chaotic Good, as are Fred and George. Percy is Lawful Neutral, while the rest of the clan seems to be hovering around Lawful Good
Albus Dumbledore: Agreed. Like Harry, he's willing to put everything else aside for the greater good in a form of penance for his youthful arrogance (which explains why he's willing to give everyone else a second chance).
Riddle/Voldemort: Neutral Evil. He's only in it for himself, which is the epitome of NE.
The Malfoys: Lawful Evil for the most part. Work within the framework for their own benefit, which Lucius and Draco certainly did. Narcissa would be more True Neutral I think. Bellatrix would be Chaotic Evil.
Snape: I'd go True Neutral. His main goal seemed to be avenging Lily after her death, and he was largely willing to do whatever it took, good or bad. Of course, how much of his attitude was acting to make Voldemort's followers think he was on their side is up for debate.
(names above added by me for clarity)
I have to agree with all of these assessments.
For other characters, I'll add that Dolores Umbridge looks LE to me, tending towards NE.
Fudge, and other members of his administration in the Ministry, I'd peg as LN- willing to do whatever it took to keep order and unwilling (even terrified) of accepting change even when evidence of its inevitability and fact was presented.
Rita Skeeter, I'd say is probably TN- the best example of it in the series other than Snape- though with a tendency towards CN since she appeared willing to break rules of courtesy (at the very least) to get her stories.
Hagrid is almost certainly LG, accepting of rules even when it hurts him and those he loves but willing to go along with authority figures he trusts even when they themselves break established rules.
The Dursleys are probably TN with a tendency towards NE, though Dudley certainly reveals himself as moving away from Evil in book 7.
Xeno Lovegood is a wonderful example of CN behavior, IMO. He generally rails against the Establishment at every turn, though in a generally benign way rather than destructive. When his buttons are pressed appropriately by the bad guys, he betrays people he himself was exhorting others to ally with, but his reasons for doing so are sympathetic (even if cowardly).
Crabbe and Goyle are probably NE with a tendency towards LE due to Draco's influence and their constant toadying up to him.
That's all I can think of for now.