J.K. Rowling has a tough choice. Already considered the richest woman in Britain, she's soon to be the richest person in the world. Betcha'. And I'm all for it.
While I think J.K.Rowling deserved her success, I'm not altogether sure that that much money should all go to one person.
However, if the publishers are panting for Harry Potter e-books, then that only illustrates the value of electronic rights for all authors. Beware of signing them away just to get a print contract, as many of us did.
I think the answer is: it'll be both old and new fans. That's certainly what the publishers are thinking.