I finished reading the book at 2:17 am this morning.
What a twisting and turning. But I have some radical thoughts on what took place:
1. Draco Malfoy is a sycophant--someone who sucks up to others and appropriates authority for his pathetic boasting. He has nothing of his own--no real strength. Of course he was incapable of murdering Dumbledore. He was a toy Voldemort was using to punish Lucius Malfoy.
2. Snape is really a good guy. Naturally, he told Dumbledore what Draco would try to do, and Dumbledore told him to let Draco try. It is in Dumbledore's character to let Draco attempt the assasination in the hope that Draco would realize he doesn't have murder in him and reform--cross over from the Dark to the good side. Remember what Snape said to Dumbledore that Hagrid overheard, "You take too much for granted."
3. Dumbledore ordered Snape to do what Draco couldn't--that is, when Draco had his chance and his nerve failed, Snape should do it. That's why Snape entered the Unbreakable Vow. But he had second thoughts, which is why he told Dumbledore, as overheard by Hagrid, that he had changed his mind and didn't want to do it anymore.
4. But Snape went through with it. The hatred on his face when he murdered Dumbledore was not hatred for Dumbledore, but hatred for what he was doing. Remember that Dumbledore, as overheard by Hagrid, told Snape he had agreed to it and that was that. What seemed like Dumbledore pleading for his life, which was out of character for him since he had just faced down the others without a means of stopping them, was actually Dumbledore pleading for Snape to go through with it. He could hardly have ordered Snape to do it in front of Draco and the others. He had to make it seem like he was pleading for life.
5. The key to this is in Book 5: Order of the Phoenix. When Harry fell for Voldemort's scheme and went to the Ministry of Magic, but tipped Snape off obliquely, that is, in language only someone in the Order could figure out what was meant, Snape contacted the Order and sent them after Harry and the others. If Snape was really with Voldemort, he would have claimed he was unable to understand Harry's statement, with his usual sneer, and no one would have suspected that he caught the meaning and declined to do anything. Then Harry and his five friends, fighting a dozen Death Eaters, would have been overcome and died.
Plus, Snape saved Harry as he fled Hogwarts. We have only his word that Voldemort said to save Harry for Voldemort to kill.
6. Dumbledore stupified Harry not to protect him, but to keep Harry from fighting to save him. Dumbledore wanted to die.
7. Why did Dumbledore die? He was old and tired, but that would be no reason for Dumbledore. He was the only one who could take on Voldemort one-on=one (excepting that Harry somehow has to be equal to Voldemort in order to stop him.) No, he had a reason, which we can only guess at and hoep Book 7 will enlighten us (and that we won't have to wait more than a year for the last book of the series.) Could it have been to restore Harry's protection--Dumbledore died to save him? It seems far-fetched. Anybody have another idea?
We know this much: Harry has to face Voldemort and end his career of evil/murder/crime/torture forever. Harry has been through six books and has earned that right in the readers' minds. The author cannot deny us that satisfaction, although how she will set it up and accomplish it remain as mysterious as ever.
I thought that Dumbledore would die before the end, but I had believed Voldemort would kill him, and somehow that would clear the way for Harry to stand before Voldemort equal in power, much as Dumbledore would. After all, the continuous comments about Harry's mediocre powers come from his enemies: Snape, Draco Malfoy, Voldemort. No one really knows what Harry can really do, except in Defense Against Dark Arts, because Harry is lazy and doesn't try in his other subjects. Harry's father was an exceptional wizard, and we finally learn that his mother had exceptional talent in other fields. The only thing Harry lacked to be equally as good was nurturing as a child.
Dumbledore's career is as much a mystery as ever. I thought that after he died, Fawkes would attach himself to Harry. But Fawkes left Hogwarts, which opens the question of just why he became Dumbledore's pet in the first place. I had wondered how Phoenix's passed from one owner to another at the owner's death, since Phoenix's have eternal life. Perhaps that will be a sequel (prequel?) after the series is completed. The author will issue supplementary books such as a biography of Dumbledore.
Finally, a note on Kreacher. Poor Harry, like Robert E. Lee and other Southerners, he found himself, through inheritance, the unwilling owner of a slave. Lee was already at work freeing his slaves when the war intervened. It is my fervent wish that when the battle with Voldemort is completed, and the Dark side is vanquished for good, that one of Harry's first acts is to give Kreacher clothes. After all, if he needs a servant, Harry has Dobby, who would help him as a free choice, and Harry would pay Dobby for it.