My guess is that it could be Dumbldor....why do I say that? Well, in the last movie, or the book "Prisoner of Azkhaban", Harry shows that he is a great wizard in the making, or actually is a great wizard, he just needs to accept it.
Dumbldor is going to have to fight the Malfoys and all those who are on the dark side and he is quite old. Someone is going to have to take his place eventually and my guess is that it is Harry.
Of course, she has said that she is not making any promises that Harry survives through the 7th book. Soooooo......it looks like she would like to make us keep guessing and hope that nobody we truly are attached to has to die.
My vote is that Hagrid lives forever!! He is my favorite character, other than Harry. I just am not willing to make any bets on who is going to survive however. She killed off Sirius Black and so I am guessing it could be Lupin or any other one of the characters that Harry has become fond of. My fear is that eventually its going to be Hagrid.
However, I have a interesting thought......what if Snape turns out to be a hero after all and saves Harry and dies himself, confessing how he loved Harry's mother and would never let any harm come to her child because of that. It would be an interesting twist. We shall just have to wait and see what Rowling has planned. But Snape being a hero would certainly be unexpected.
"Sigh", I have become addicted to the Harry Potter saga, much like I did Star Wars and Anne Rice and Lord of the Rings.
Of course, there is also Laurel K Hamilton, who writes all these steamy, paranormal novels about vampires and werewolves who have hot, lusty, sex throughout her books. But that is another subject for another time...............