I am caught in a Harry Potter vortex at the moment - having watched movie #3 (a present from a friend) I trotted off obediently to buy movies #1, 2, and 4. I seem to recall the same thing happening when I finally gave in and read the books.
What's nice is that it's been so long since I did read those books, I don't mind a bit that there are huge hunks of them left out to manufacture a comprehensible 2 hours of film.
Mostly I'm absorbed by how drool-worthy the Hogwarts architecture is. I remember reading somebody's comment on some website or other that it is terrible the way the Harry Potter series fetishizes boarding school and thinking, why yes, it does! but I didn't, and still don't, find that nearly so terrible as I do the fact that I will never get to live there.
Also: it has to be said. I never hated Snape as I ought to have in the books, and I definitely do not hate watching Alan Rickman scraping the hair back from his face to flash another bewildered yet malevalent look. I think it's physically impossible for me to hate an Alan Rickman villain; from the time I first saw him - doing the dirty in The Barchester Chronicles back when it first came out - I was painfully aware that while I was not meant to, I quite liked his Mr. Slope. He was so deliciously greasy and such a sad character. It was a surprise to read the (excellent) book afterward and find that Slope was not appealing at all.
That's another take on how to write a villain people care about, isn't it. Ideally s/he is Real and Relatable or the evil doesn't work, and for me, Snape/Rickman always works. A good bad guy is just interesting enough that no matter how detestable... you wish s/he liked you.
If I ever get around to putting down my TV remote and my knitting needles and write a paragraph or two with a villain in it, I will definitely have to keep that in mind.