It seems that my predictions were right.
1. Snape is the Half-Blood Prince.
Tick. He certainly was. I wasintrigued by the use of the Potions book to introduce the HBP. Pity, though that none of the junior wizards seem to be able to learn anything from the books other than to follow instructions. Nobody teaches them how to think for themselves and apply principles. I don't envy their university lecturers at all.
I hadn't predicted Snape's DADA appointment (thought that was going to be book 7). Nor did I think he'd turn out evil. It seems an oddly flat and uninspired way for Snape to end up. Must admit I am disappointed in how Snape's betrayal was handled/foreshadowed throughout the book. Maybe there will be some strange redeeming twist next book? Like Dumbledore asking Snape to kill him to protect Snape's cover? Convincing Harry of this will be... amusing.
(Edit: Just read a couple of posts on my flist as well as done some more thinking. I now think that it wasn't the killing curse that killed Dumbledore - on previous occasions it has looked rather different after all. So a Snape-twist seems all the more likely next book, and I can stop feeling vaguely disappointed, at JKR's sudden apparent lack of finesse.)
2. Dumbledore will die.
Tick. Sob. I liked the way she managed to bring him more to life before bumping him off. But the way he talks about his great cleverness is somewhat on the bloody irritating side.
3. Harry will get a girl-friend - probably Ginny.
Tick. This was actually rather cleverly handled and nowhere near as saccharin as I thought it might be. I hope she doesn't give up on him. After all... Dumbledore has repeatedly told us of the power of love.
4. And then probably dump her in some heroic nonsense of the type that got Sirius killed.
Tick. But not at all in the way I thought! I liked the way that was handled. She's turned out to be a strong and interesting character.
5. Ron and Hermione will continue to bicker, but not *quite* get around to 'going out' with each other.
Tick. What more can I say? I hope they get it together eventually.
As for Nymphadora Tonks and Remus Lupin: oh yuk, yuk, yuk! If you are going to pull such sickly sweet relationships out of your hat, do it with more than a few bloody cameos. I preferred Harry's original thought that it was Sirius. I'd guess she was in love with someone myself, before Harry did and thought it might have been guilt about Sirius that changed the Patronus. But the Lupin thing. Ick.
Anyway, I have a new prediction, for HP7: R.A.B.= Regulus Black. At least it could be Sirius little brother, because I don't think that JKR is going to introduce a completely new new character for this. I may, of course, be wrong, but it's almost certainly who my R.A.B. would be, if I wrote HP.