Hennessey + Ingalls
a wonderful Architectural and Art bookstore on the Santa Monica Promenade; Opamp Technical Books
– killer technical book selection located in dingy and wonderful Hollywood; Book Soup
– nice general interest bookstore on Sunset Boulevard; Midnight Special Bookstore
– cool indie bookstore, great selection, on the Santa Monica Promenade.
Some of these stores also allow you to buy online.
(Forgive me this nostalgic moment)