As to the Angel, most of us Geordies have a lot of affection for it. But I'm biased, as I think Anthony Gormley is Britain's best living artist (sorry, I'm not trying to hijack the thread, honestly
).
I found Stonehenge disappointing because in my mind, and from all the pictures I'd seen, I thought it would be huge. And it wasn't.
I find the list of the most popular interesting. Alnwick Castle??? It's quite a nice little castle, but I think Harry Potter may have had something to do with the recent popularity.