Oxfam book shops (nothing I love more than looking in them!).
Also buy from Amazon.
There used to be a fantastic shop in Camden called Compendium...it had a good attitude and, I suppose, shared my view of literature. The guy that worked in there had similar taste to me so he would always tip me off about what was worth reading. Who has a relationship with their bookseller anymore? Just people selling us books...and shops pushing stuff at me that, usually, I have no interest in...