Here's something to discuss...
Facts from Mugglenet.com (some were omitted)
These are facts straight from the mouth of J.K. Rowling, and were gathered from numerous online chats with her. Everything here is confirmed.
Random facts about the book
*There will be a new Minister of Magic, no more Mr. Fudge.
*We will find out what happened to Hagrid's half brother Grawp. He will be a bit more controllable in book 6.
*The Dursleys are in the next book, but Harry's stay with them will be the shortest yet. In book 5 he stayed for 4 weeks, so we know his stay will be less than 4 weeks.
*Cho Chang will not be a romantic interest of Harry in Book 6, however there will be a "little romance" for Harry says JK.
*****In books 6 and 7 we will find out exactly why JK killed off Sirius.
Harry becomes even more powerful in book 6.
*In books 6 and 7 we will find out why Dumbledore trusts Snape.
*We will find out what happened to Wormtail AKA Peter Pettigrew
*More about the animosity between Snape and Sirius will be revealed in the last 2 books.
*****JK has said that giving away the form of Snape's boggart and patronus says too much. We'll definitely find out what Snape's worst fear is, and it'll be important.
*We will find out what exactly Dudley saw when he looked at the dementors.
*****The reason Voldemort and Harry both didn't die when Voldemort tried to kill Harry, will be revealed.
*****We will see more of Draco's mother, Narcissa Malfoy, now that Lucius is busy.
*****We'll learn more about Harry's scar in the last 2 books.
*Moaning Myrtle will make an appearance again, as will Tonks.
*****More about Voldemort's birth will be revealed, thus helping us understand why he is so evil.
*Muggles begin to notice "more and more odd" occurrences in book 6, says JK.
*****The wizarding world is really at war in the sixth book.
*Harry will tell his dearest friends about the prophesy after it sinks in to him.
*We will learn more about Harry's relatives, including his grandparents (though JK says they aren't really important to the story)
*We will find out what happened to Sirius's motorbike.
*It's very important in the plot that Harry has his mother's eyes, and that her wand was very good for charms.
*During an interview for Kids BBC, Victor Greensteet (reporter) asked Rowling if Harry would have a dragon for a pet. This is what she replied: "You can't tame a dragon, no matter what Hagrid thinks. It's simply impossible. So no. He has more common sense. He MAY have a different pet in the future, but for now, I won't say anything else". (This could have been buckbeak, but I'm sure we can expect more pets)
*The choice between what's right and what's easy will be a pillar of the plot in Harry's last 2 years at Hogwarts
*****Harry's parents' profession will be a big part of the plot.
*****Something HUGE will be revealed about Lily Potter.
hmmm... So why DOES Dumbledor trust Snape? There were so many Death Eaters that claimed to have come back to the good side, like Lucius Malfoy, but who were actually full fledged supporters of Voldemort. Why couldn't Snape be one of those? I know that he started to spy for Dumbledor, but what's to say that he's not spying back for Voldemort, too?
Sorry this is so long, but it's been bugging me for some time....