OMG! Sorry to jump into the thread like this, I haven't read all the posts yet...
But I've just finished reading it. Well, I had my suspicions as to what will happen, mostly due to the reviews I was getting on my fanfic. They didn't tell anything, there were no spoilers, but reading between the lines, I've aquired this feeling that Snape's not going to end well. And then I saw something about Dumbledore, put it together and... I expected him to kill Dumbledore and yet it still came as a shock. I that Snape is the Half-Blood Prince after seeing the HBP's handwriting, Snape has the same handwriting when he writes his O.W.L.s exams on DADA. So... one of my wishes came true (Snape being the HBP), but... him killing Dumbledore? I can hardly breathe, THAT is a shock! I was actually shaking while reading it and then I've decided to take a whole pill for my heart beat (I'm taking them to put my pulse back into normal) to somehow still my heart. I'm fine now (JKR, you've nearly killed me, you evil thing!!! hehe...).
Now I have two theories about Snape:
1. He is truly evil and he's VERY evil, all the time he's been at Voldie's side, fooling even such a great wizard as Dumbledore is... was... (if he did, than I still like him for his ability to fool him, what an actor!). The reason why I think is that that when Dumbledore drinks that green potion at the Horcrux, he obviously sees or remembers horrible things. What if Snape had taken the Horcrux and put there something horrible for Dumbledore to see, possibly his future betrayal... That's why Dumbledore sounded so frightened when Snape went to kill him.
2. Snape isn't evil, he was either acting on Dumbledore's orders (Dumbledore would be willing to sacrifice himself so that Snape might keep his cover) or he was behaving like a Slytherin - saving his own skin first or Draco's skin (because if he failed to protect him, he would have died). Would someone as wise as Dumbledore trust Snape only because Snape said that he was sorry for what he had done? There has to be more to it... or am I being too optimistic again?
I'm not yet ready to comment on other things...
But I liked the book a lot, though some parts felt like a badly written fanfiction, sorry. All those romances, why suddenly? And all that snogging... Although I liked reading about Voldemort's youth, I felt that it was written a bit superficially.
Dumbledore's death and funeral reminded me of something, I just don't know yet what it is. King Arthur maybe? And something from Gormenghast...