It's better for Harry Potter, an actual book and it's longer than 40 pages, to be pop culture than some of the other trash out there. Harry Potter is actually pretty intelligent for a kid's book (though I remember the narnia series being pretty intelligent too but I was in the third grade, the mutant ninja turtles were my idols). The fact that I've seen kids lugging a 900 page book around and supposedly they're actually reading it and it's not just carried to break their backs down like their school books makes me enjoy the phenomon.
For me, it's hard to detest something that could potentially bring the IQ of pop culture up as opposed to say Paris Hilton or "Deal or No Deal" which are surprisingly easy to detest.
Though I must admit, the last book bored me to tears and I don't think it's the best thing *adults* could be reading (you should know what your kids are reading for sure but other than that). On the other hand, some of my friends who've never picked up a book for enjoyment in their lives and have no kids have picked up Harry Potter so, I guess if that's the case something is better than nothing.