Tardis with ladders.
Knowledgable, welcoming and helpful assistants. A very wide selection of books. An attractively laid out bookshop. I went in to find a collection of Philip Larkins' poetry (His work wasn't in two of the other main Edinburgh bookshops at all). Not holding out much hope I asked, 'I suppose you haven't got any Philip Larkin?' The answer was a cheerful, 'Philip Larkin? Oh, I think we might manage that! Right this way!'
Now the Edinburgh Topping bookshop had books from floor to ceiling and that assistant was up a ladder and back down again with an armful. The book I wanted was there. I could happily live in that bookshop. It's not dissimilar to the Tardis.