It depends on the type of books that you love to read; whether fiction or non-fiction. For many people Ariel Booksellers first comes to mind. They have a cute children's area, and the shop is spacious with high quality books in Darlinghurst. Love the luxe travel guides in particular, so chic and trendy; you feel so opulent with something so simple. Mature customer service, and the Hill of Content in Balmain is also worthy of a mention, as well as Bray's Books. What do you think?
If your into self help and personal development books (as a life coach, abundance and prosperity writer; this is a genre that just gravitates to me as easily as travel books do, so forgive me for that) Phoenix Rising Books in Glebe would top my list. They also sell high quality spiritual chill out CDs, and the shop is so beautiful and inviting. It is easy to develop a great conversation with the staff. Also Adyar Bookshop in the city is also worthy of a mention. It was better when they were located in Sussex Street than the now Bathurst Street; they had more space in the previous locale than what they do now, so it is difficult to give the great talks that were once possible. More like a library now, yet the stock is of high quality.