I was a freshman in high school when I received the first two books for Christmas. Needless to say, I devoured them, and then every subsequent book in the series as well, as soon as they were published. For the sixth book, I stopped at a Wal-Mart at six in the morning on my way to an out-of-town wedding to pick up a copy - and seriously considered skipping the reception to hide out in my hotel room and read. For the seventh book, I waited in line at midnight, then proceeded to stay up all night to read it. I was done by eight in the morning. I couldn't risk anyone spoiling anything for me!
I had been a voracious reader before Harry Potter - these books didn't change my life in that way. But it did add magic to my life. There's just something about these books that sets them apart, no matter how many other books we've read.