You absolutely have to go to Barter Books. It is the most fantastic second hand bookshop in THE WORLD. The books are laid out in a way that makes you want to look at them in the beautifully restored station house. It was simply heaven and I was very restrained and only bought two books. The building also features a list of all the people who worked there over the years including my new uncle David Appleby :0)
A few pics at flickr if you want to see more.