Dainsie has made this summary of some of the most prevelant theories for Book 7.
You can read the full discussion thread
here (currently password protected to prevent HBP spoilers). Password: (you need the book to find out) The fourth word in Chapter 16.
Quote:
Originally Posted by Notes from Dainsie
I was originally going to go with two theories for both the return to Hogwarts and the final battle, but there wasn’t enough info on the not returning side, plus most people that posted and me think they will go back, so I just went with that one.
Most of the posters seemed to think that the battle would be at Hogwarts, so I used that, but didn’t give any info on the result, so I just used the most common one and the one I think and hope will happen.
~Dainsie
Book 7 Plot Theories
Harry will return to the Dursley’s, keeping his promise to Dumbledore. The duration of his stay will be short, only remaining long enough to renew the charm upon him for the final time. He will tell the Dursley’s that he will never see them again. Uncle Vernon will be ecstatic, but Aunt Petunia may possibly reveal a side of her that we have never seen before, maybe showing that she knows far more than she lets on, and possibly reveals something important about Lily.
He will then travel to the Burrow along with Hermione, and meet all of the Weasley family that are there for Bill and Fleur’s wedding. It will be in the garden of the house and a simple family affair. Harry will find it hard being around Ginny who clearly still wants to be with him, but she does understand what his reasons are and respects and admires him for that, as does Mrs. Weasley. Harry definitely wants to be with her too, but his worry that she will come to harm because of him assures him of his decision.
Hogwarts will re-open but the number of students that return is smaller than most years. Some parents will be to afraid to separate their families, especially now that Dumbledore is gone. Professor McGonagall will become Headmistress of the school. Professor Slughorn will stay on as potions master and become Slytherin Head of House. He may become slightly less selective and elitist, after being so wrong about two of his ‘favourites’. Hagrid will become the Gryffindor Head of House, and Grawp will play a part in the story line. The post of Defence Against the Dark Arts teacher will be taken by an Auror and will teach the class much more practical defence.
Harry, Ron, Hermione and Ginny will all return to school, along with Neville and Luna. The trio will use all the resources that the school has to offer to try and track down the Horcruxes, not really interested in finishing their education, though McGonagall will try and make the school run as normal as possible. Harry will visit Dumbledore’s painting for advice and possibly find clues and help that Dumbledore left behind to aid him. Ginny, Neville and Luna will try to help but Harry won’t let them, fearing for their safety, though they protest vehemently and still try. Harry is still slightly uneasy even about Ron and Hermione’s help, though he realises he needs their talents to help him and that they are stronger together. In the holidays they use that time to try and hunt down the Horcruxes, as they are now of age and can use magic freely. They possibly travel to Grimmauld place (remember there was a locket there) maybe left by Regulus, and maybe Godric’s Hollow.
The final battle between Harry and Voldemort will take place at Hogwarts. Voldemort will be defeated at the hands of Harry, though a lot of people will fight. Snape will play an integral role in the whole of this, but as to what side he will end up on we are not sure of until the very end. Harry’s scar will disappear, severing his link with Voldemort forever. Ron and Hermione will get together, as will Harry and Ginny.
The final chapter of the book will be like an epilogue, or will at least answer all the lingering questions that we have. We find out about what happens to all the characters, more about Harry’s family throughout the book, and what happens to them all after they leave Hogwarts.
Then we all cry because it’s over…
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Thanks to Dainsie for the work in putting this together and to all the posters in the
HBP Spoilers forum!
Feel free to make (HBP spoiler-free) comments here, or better yet, go to
the original thread and speculate away!
Source:
Dainsie 
What Will Happen in Book 7? 
I think harry will die and so will ron and herimone.
harry might be killed because his avada kadvra curse backfires during a dule with lord Voldemort
(the same thing should happen to the dark lord) 
I'm looking forward to harry's final fight with voldemort.However,I'm also so worried about harry and his friends.
