The publicity machine has certainly helped hype them up, but I for one love them. Whether I'm reading them for the first time or the sixth time I am still totally bowled over by JK Rowling's imagination and when I'm reading them I actually find myself believing that Hogwarts could actually exist.
But yeah I do think the publicity surrounding the books and films each time they are released has definitely helped with their success. I mean the first book or two weren't all that successful when they were first published, were they, so something must have happened to trigger off this whole HP phenomenon - I just can't remember what it was.
Still as a booklover who is always reading, I think any publicity that HP gets is definitely a good thing. It's certainly helped get kids reading again.