Like the other posters, I really enjoyed Durham. Even though I had arrived in the early morning on a night bus from London and had to wait several hours for anything to open, the city didn't fail to impress me with its considerable charm. The cathedral is one of the greatest in England, and a wonderful example of Norman architecture at its prime. The castle is also very interesting, but it's now used as a university, and not everything can be seen. By the way, when I was there, the late Peter Ustinov was still chancellor (or whatever his exact title was). I found this entertaining, even though the post is probably only ceremonial. The city of Durham is also pleasant and not too big, meaning that the cathedral and the castle can be seen from almost anywhere, without any modern buildings blocking the view.