I like Olbermann’s prediction waaaaayyy better than mine. (You can tell I haven’t got my book yet — it was pre-ordered and may be waiting for me when I get home). Here it is:
Harry’s scar is a Horcrux.
Harry has to destroy himself to destroy Voldemort.
Harry is about to sacrifice himself when Snape the Saviour intervenes and gives Harry the choice — destroy the scar and lose his magical powers.
Harry loses his magical powers, and Voldemort (together, presumably, with Snape) is killed in the final conflict.
The series ends, but Harry Potter doesn’t.
I think he’s got it. Watch it for yourself.
And if you’ve read the ending, DON’T TELL ME!!! I’m shutting down all comments on this topic until I read the book for myself.