And I have to say this:
I know I've only been in England for a month, but I have to say, I don't think that as an American I really realized exactly how much of Harry Potter is based in English culture. I'm glad I'm learning now, but wow. One of my friends pointed this out as we were on our way into Norwich the other day, because the bus was really jerky and she said that it was totally obvious where JKR was getting the Knight Bus from. And there are just so many other things, it's really funny.
We also got to take a trip to Oxford and see Christchurch College, ie one of the places they filmed Chamber of Secrets.

The staircase Tom Riddle was standing on

And again

Me doing a really bad Tom Riddle impression (and simultaneously being told what a dork am I for doing this)
Hogwarts-looking hallways:


And what looks like the Great Hall ceiling to me, although I don't think they filmed the Great Hall scenes there (but I don't know)

And that's all I've got!
Any other cool HP sites I need to visit while I'm in the UK?
Rachel//Ravenclaw