
The poll surveyed over 500 people from GlobalTestMarket (an online survey website) to see what people thought would happen in the new book. I'd have to agree with all of the people who suggested Dumbledore is not dead (personally, I think he is either dead or faking it, but regardless his "death" is an intentional move to get Voldemort to trust Snape.
On Snape, readers are torn... a whopping 48% still think that's he a good guy, while the other 52% follow the simplest solution that Snape has indeed turned back to the dark side.
As for the fate of Voldemort, 77% people think that he will indeed fall at the hands of Harry, but over 60% think that Harry will not survive the end of the book. Personally, I think Harry will survive (regardless of how dark the stories have gotten, Harry Potter is still a children's franchise, and I think the series can end just fine without killing off the main character), though I can't discount the possibility of him sacrificing himself to make Voldemort vulnerable - a possibility 52% of people think.
You can read more of these interesting statistics at: http://www.gmi-mr.com/gmipoll/release.php?p=20070717