Well all, I've finished the book as of 9:54 PM yesterday and I have to say....
I think Snape can't be wholly bad-He wants to make sure that Harry maintained a pristine soul, doesn't he, telling him that there will be no unforgiveable curses for him? Hes' protecting Harry the only way he knows how, and my suspicion is that he's doing so as a debt to Dumbledore, and because he doesn't want to be a deatheater, but has no choice in the matter.
I also understand why everyone doubted Harry. Malfoy has shown no signs of extreme evil up to this point, merely bigotry, and jealousy that his family encouraged re: Harry Potter. It was viewed by most adults, and children as an increase in the rivalry between the two 'house heads" as they are socially viewed. Only Harry, the only person who has had a full understanding beyond Dumbledore could have understood just how sinister the things were that were happening. Except Dumbledore, who knew what Malfoy was up to, but didn't expect it to come about on the day that he drank the weakening potion. Dumbledore had no fear of death, however, and also no fear of Malfoy actually being able to go through with it. Even though a deatheater, I suspect Malfo was again merely following the only truth that he had ever known- that which his parents raised him to beleive. Maybe Dumbledore Saw this in him.
Snape, however, could not allow Malfoy to be the one to kill Dumbledore, for whatever reason, perhaps also as a debt to Dumbledore- to keep Malfoy as innocent as he possibly could- Why, I don't know.
Next year, I don't tink there will be a hogwarts, but No, Harry's not going back-I simply hope that he manages to work out more spells than this year- I know he's a sinch for dark arts, but he'll need more than that to do well in the real wizarding world.. *frown*