My personal feeling is that Harry is going to live - if for no other reason than the fact that Harry was intended to be the hero that children feel they can BE. If, after investing all of her energy into building up this very "real" feeling young boy, Rowling killed him off, I think that would send a VERY different message than she intends... yes, the books are dark, and harsh, because they are supposed to be a lesson about the difficulties of life - but they are also about the ability to perservere, win through, and come out on top. The good guys win, but at a great cost. So I don't think Harry is going to bite the bullet.
That being said, I have a feeling that Neville is probably going to end up on the wrong end of a deadly curse, that either Dumbledore or Black will end up not being dead after all (or WAS dead, but will somehow be brought back), and that one of the Horcruxes will turn out to be something left over from when Harry's parents were killed, since that was supposed to be part of Voldemort's final triumph.
I'm 50/50 on whether or not Ron is going to die - I think it's a very strong possibility, but I also think that JKR has a sense of self-preservation, and knows she would be in danger of assassination if she killed him off... there's a lot of lovin' for Ron on the net.
Incidentally, has anyone here read the fan fiction called "Harry's Last Adventure" over at
www.veritaserum.com? The author took particular pains to explain and justify pretty much ALL of the loose ends that were left in the series after book 6... aside from the fact that it's fairly smutty (as pretty much all fan fiction is), I think she actually managed to accidentally get several things right. She also pretty much perfectly captured Harry's teen-angst-stupidity thing that always felt so real (and annoying) to me. I'll be interested to see how many of her leaps of logic turn out to match up perfectly with the real story.