I've never read any of the books, but I do own all of the films thus far.
I like the fact HP is a universal among its fans... As is Star Trek, Star Wars, Lord of the Rings and countless other works of fiction... And that is liked by so many fans across the globe (like beforementioned series). It is a testament to the power of storytelling, aka JK Rolling, and it re-affirms the belief that good storytelling really is a timeless art that can't just be "bought" like Hollywood and a lot of others think.