Half-Blood Prince

I picked up my copy of Harry Potter & The Half-Blood Prince last night at midnight and read for a couple of hours before bed. This morning I ran errands and then read all afternoon. I finished the book at about 6. I am not sure what I think - my opinion at this point is colored by my annoyance (common when finishing one of the later books in the series), that the book seems to create more loose ends than it ties up, that Rowling has left a whole lot to cover in the next, supposedly last, book, and that, at this point I have no one with whom I can discuss the whole thing.