Powell's City of Books in Portland, Oregon, is magical. I found the shop on a business trip to Portland and was amazed. I spent the better part of two days, whenever I wasn't in a meeting a couple of blocks away, wandering the multiple floors of books. Bookstores were, and are, so awful in San Francisco (and now Los Angeles) that a weekend "getaway" trip for me is one to Portland, where I spend a day shopping for books and a night usually discovering some odd bars. On the west coast, plane tickets to and from Portland are the cheapest.
There are a lot of fantastic hotels and restaurants around the bookstore, and if you love books, bring an extra bag with you.
Image: screen grab