One of the interesting parts of Harry Potter is, of course, not just that it's a compelling series of books, but that it's become a whole cultural/social phenomenon, with parties, and stories. I think that's part of why the hysteria is so particularly strong for this last book--it's a bit of a social break (and maybe that's why the most recent Star Wars movies stirred up such ire among fans--because the films' suckage (I know that's not a word) spoiled our ability to continue a social phenomenon that would have partially connected us back to our youth).
Our story: my father-in-law purchased book #7 for us, from a bookstore in CT. We live in Boston. This meant that he would have to mail it to us, on Monday or Tuesday, and we'd get it by the end of the week. To be honest, I'm third in line in our house, behind my wife and daughter, so I didn't really care. But Tracy really, really, really couldn't wait until the end of the week, and we didn't want to buy an extra copy. So Saturday morning, she drove down to Connecticut and her father met her half way, and she picked up the book at an exit somewhere in the middle of nowhere. Now we have our copy, and my wife gets to read it before and after work, and my daughter reads it during the day. They're struggling not to talk about it in front of me, and we're all on careful media diets to avoid spoilers.
I'm told that approximately a good chunk of all blogs have mentioned Harry Potter this week, so I guess I'm part of the club now.