Just to chime in with my two cents: I read the first four one after the other. Went to a midnight party for the fifth book, started it, managed to misplace it (though I still don't know how I managed to misplace a book that's over 700 pages long), then once I found it, never picked it up again. No particular reason. Just other stuff to read/do/worry about. When I first got into the books, I was REALLY into them - visited HP websites daily, got sorted (Hufflepuff, natch), played virtual Quidditch (okay, I'm lying about the last one) - but after a while, I pretty much got over it. I do plan to reas OotP eventually, and I will buy HBP eventually. But no, you are NOT the only one whose interest has waned. So there.