This is a bit of a 'retro-post' as I visited Barter Books back in June but forgot to post about it! Located in Alnwick in Northumberland, Barter Books is one of the best bookshops I've visited.
The bookshop is located inside an old railway station and houses hundreds of books as well as a little cafe, and best of all a miniature railway runs round a track above the shelves!
It's also the place which kick-started the (slightly too ubiquitous!) Keep Calm and Carry On phrase into popularity. An old poster from WWII containing the slogan was discovered in a dusty box of books and put on display in the shop. Its design was so popular that customers started asking for a copy. You can hear the story of the poster and the shop in this video. If you're ever in the area I'd recommend a trip to Barter Books, I just wish I could have stayed there longer!
(PS This year has been a good one for bookshops - I visited Hay-on-Wye aka the town of books in May!)