Newbie
I'm new here. So forgive me if I digress to ideas discussed earlier on this topic.
I have a strong feeling that Dumbledor is not dead for the following reasons:
1) J.K Rowling said once that Tolkien (Lord of Rings) and C.S Lewis were some of her favorite authors. The undeniable similarities between Gandalf and Dumbledor COULD be a foreshadowing of a supernatural resurrection.
2) In the series J.K Rowling uses symbols to enhance and foreshadow characteristics and events (if you don't believe this, google it. Numerous books from acclaimed professors have discussed the symbols in HP). Notice that Dumbledor's pet, confidant and (from what i heard somewhere, though i've never read it) patronum is a Phoenix, an animal that resurrects from its own dust.
However, I'm assuming that Dumbledor has some power to overcome death. A counter-argument i read from an early post states that Dumbledor can't be resurrected because no other character in the series has done so. But, has anyone in Lord of the Rings resurrected prior to Gandalf's? Or how about Aslan's? I'm just being open to the idea.
Another possible way Dumbledor lived is a theory that Aldistar pointed out, which I find very creative and interesting.
Quote: think that Dumbledore isn't dead at all. I think the RAB person was the one that Snape blew off the roof that night disguised as Dumbledore with the polyjuice potion. It was all an elaborate hoax to trick Voldemort into thinking Dumbledor was dead and that Snape really was on his side. Snape saved Harry's life at the end and pretty much told him to just lay low. He wouldn't have done that if he wasn't in on something.
Whoever RAB was sacrificed himself to further the fight against Voldemort and place Dumbledor in hiding. Remember when Draco was hesitating and said he had to do it or Voldemort would kill his mom? Well Dumbldore told him they couldn't kill someone who was already dead, that they had ways of making it seem as if they were already killed.
By killing the Dumbledore on the roof (even a fake one) would uphold the unbreakable vow that Snape had to take. That way the world thinks Dumbledore is dead and Draco is spared. (I think he will go good as well-as good as his stuck up ego will allow, anyway).
I'm not saying dumbledor is dead. But I won't believe that he is until Rowling herself says so (just like when she said Sirius is dead for sure).
Finally concerning Snape: Maybe he knew that by telling Vold abt the prophesy, he knew that the would bring abt his demise. I'm saying that he 'slipped' to vold a bit abt the prophesy on purpose to kill him.
Another prediction from mills75 that Draco will switch sides...
what an interesting idea!