I currently work in a bookstore, and I have had the opportunity to work in both large format and small format.
The large format store has a coffee shop, big comfy chairs for reading, and at Christmas, the whole place is decked out with Christmas trees and smells like pine. The one I worked at had large windows, and it was always sunny in the store.
The small format store I work at now is in the mall, and it's equally cozy. We don't have room for chairs or a coffee bar, but we do have rows of books, and it's quite bright. Honestly though, I think the best thing about the atmosphere is the workers. Both stores have treated me as if I am a family member, and everyone cares about everyone else. I love coming to work to share my favourite books with customers, but the workers make working at the bookstore a great experience.