This is a very interesting topic

, and what would an 8th book be about? Would it be, as Smart Owl questions, pointless, as the villain, as well as some of the good guys (some of the most interesting in my opinion - ( a world without Dumbledore and Snape, and Fred????) bit the dust, so there would be no point.
Or would it be as Eisa speculates, an offshoot like many other highly successful authors have done in the past, including JRR Tolkein, with a whole industry still churning out new tales (they even divide them into categories now: those he wrote, those he thought of, those he half wrote and were finished by someone else, those his son Christopher Tolkein wrote etc etc etc).
The thing is, I think one needs to distill the HP series into the fundamental "magic" of the books, and that, in my opinion, was connected with two critical areas: i) the desire of people to escape into a world of fantasy and ii) the deep seated nostalgia everyone seems to possess for their school days (real or imaginary), when life was new and innocent and indeed "magic" in the discoveries of who they were and what the world was about.
I think, therfore, that any new book, unless it is an offshoot, like "The Silmarillion" (Tolkein) or others, needs to centre itself on all of the fundamentals that made living in the HP world so delightful, i.e reminising on teachers, classrooms, learning, students antics, common rooms, cafeterias, crushes,, adventures, quiditch etc.
If you don't think this is true, how many of us felt that Book 7 (DH) took us away from the warmth and happiness of Hogwarts, because most of this book actually took place in situations more reminiscent of Frodo and Sam in the shadow of Mordor, which wasn't actually very pleasant or fantastical at all really - I remember wishing for a good session in the Great Hall with all of the food and merriment, which was sadly missing in Book 7.
So, Book 8 couldn't be more of the same, cause JKR killed off any chance of that, and it couldn't be a pre-cursor, cause Harry and the crew started in first year, so she has really painted herself into a corner. As for fanfic, that only exists in this VTM site, so some of you brave authors will need to pluck up the courage (as Hermione said to Ron - what a bad match that was!) and go forth and become the next JKR with a brand new series: the sons/daughters of HP????
Anyway, I think all of you who keep this site going, especially the contributors to all of the articles - ROCK!!!!!!!!!!!!!!

so keep it up - from a very occassional, slack, but still enthralled and interested, Grantland1111 (the 1111 is my birthday i.e. 11th of November hehe)