I made a list of predictions back in April for books 6 & 7. Let's see how they stand as of the end of HBP.
(Predictions that have come true are crossed out, ones that are sort of happening but not really yet are italicized.)
1. Ron/Hermione will become more canon than it already is.
2. Harry will have more romance in his life but he won't be firmly committed to anyone at the end of the series. Ginny or Luna are the most likely candidates to be his "last" girlfriend. (Well, not end of series, but end of book 6, so far.)
3. A Weasley will die, but not Ron or Ginny.
4. Dumbledore will be deader than dead.
5. More magical creatures will pop up and be important to the plot, including dragons, goblins, house elves, centaurs and/or giants. Most of these will be annoying.
6. At least one of The Trio will become Head Boy or Head Girl.
7. Draco will NOT be redeemed in any way, shape or form. (I was dead certain JKR would never humanize Draco in any way before reading HBP. Now I'm pleasantly surprised at how she's given him some more dimensions. He's no Snape, but it's a start.)
8. Lucius will die.
9. Snape will be redeemed but will probably either die or be horribly injured in the process. No. Comment. At least, not until later...
10. Neville will avenge his parents.
11. We will see the Chamber of Secrets again.
12. Lockhart will appear at least once more.
13. Percy will return to the Weasley fold. Eh, kind of, I guess.
14. Luna will be proven right about one of those crazy stories in the Quibbler that she unquestioningly believes.
15. Whomever becomes the DADA teacher in Year 6 will also be a one-year prof like all the previous ones. *sniffle* Et tu, Severus?
16. Peter will do something to at least partially redeem himself, but not before attacking Lupin with his silver hand, and will probably also die.
17. We will find out exactly why Snape hasn't been named DADA teacher yet.
18. Sirius will communicate from beyond the Veil somehow. Possibly through those mirrors that that idiot kidHarry never used.
19. The fact that wizards can't Apparate/Disapparate from within Hogwarts yet house elves can will become significant.
20. Umbridge and Grawp must die. Well, okay, that's more wishful thinking than a prediction. ;)
21. We haven't seen the last of Karkaroff. I flubbed this one. We have seen the last of him. He's taking a long dirt nap. o_0
22. A Slytherin student will be a useful good guy. If this doesn't happen I will scream.
23. We will have a detailed explanation of exactly what happened the night Harry's parents were killed, who was where, when they were there, why, etc. (Please please please!)
24. We'll finally learn what the @#$&* is so significant about Lily and Harry's green eyes.
25. Petunia is more than she appears. Either she or Filch will be the one JKR says will exhibit magical ability late in life.
26. Harry will have to face Dementors again.
27. We'll learn why Dumbledore's eyes showed that "gleam of something like triumph" or whatever it was late in GoF when he was told about the graveyard events.
28. We'll learn more about the Hogwarts Founders.
29. We'll learn more about Tom Riddle's parents and the circumstances of his birth and childhood. Big time! :D
30. Hermione has to learn to lighten up.
31. Neville's green thumb will come in handy.
32. We'll find out that Snape was fond of Lily Evans. Whether it was just admiration or all-out luuuuuuuuuurve, we shall see.
33. Fleur will show up again.
34. Harry and Co. will learn to Apparate/Disapparate.
35. The Malfoy estate's proximity to Stonehenge will come into play.
36. Godric's sword will end up in Harry's hands again.
37. Harry will make some sort of journey into the underworld. I'm not sure what form it will take, but it may involve the Veil.
38. Voldemort will lose. Exactly how, or even whether he finally, once and for all, DIES, is up for debate. Ditto whether Harry lives.
39. Harry's Quidditch skills will come in handy in battle, sort of like they did with the dragons in GoF.
40. Nagini will have a noticeable, though perhaps not terribly significant, role.
41. At least one Death Eater (besides Snape) will defect to Dumbledore's side.
42. Someone from Harry's generation will become an Animagus.
43. We'll learn Snape's patronus and boggart and it will be really cool.
44. Time travel as a plot device will show up again.
45. That weird hand artifact in the store in CoS will show up again.
46. We'll meet a vampire. If it's Snape I will fly to Britain and bitchslap JKR until her teeth rattle. (We met one, but it's not Snape. Yay!)
47. Hagrid will live but not because I want him to. :-p
48. Ginny's experience with Riddle's diary will come into play somehow.
49. At least one of Fred and George's pranks will turn into a weapon in the war. (I was right, but it was used by Draco! Yikes!)
50. Harry wakes up in his cupboard under the stairs, still 10 years old, and realizes it was all a dream, he's not magic, his parents were really killed in a car accident, and there's no such thing as magic. ... Or not. Bwahahahaha!
/April predictions
Now for my last-minue predictions from several days ago:
1. Dumbledore? Deader than a really dead thing. Probably near the very end of the book for a semi-cliffhanger. I am so good. ;D
2. We'll find out more, but not everything, about that fateful night in Godric's Hollow.
3. The Ron/Hermione ship will not sink. It may or may not become canon yet, but it won't sink.
4. Who's the Half-Blood Prince? My guesses, from most to least likely:
a. Godric Gryffindor
b. A Hogwarts student with whom we're not very familiar yet.
c. Hagrid *gag*
d. Snape OMGWTFLOLSQUEE! ;D
e. Lupin
f. Dumbledore
d. Someone we've never heard of before
Heh. So I'll have to revise my list and make some new predictions. Ah well, unfortunately I suppose I'll have plenty of time to ponder between now and Book Seven. ;)
I've got a gazillion other things to think about and write about, but not just this moment...