The pioneer in internet sales. They don't currently discount my book. Outside the United States Amazon in the UK is the British branch of the American site. Blackwell's in the UK is an academic bookseller with its most prominent shop located in Oxford, though there is also a fine one on Charing Cross Road. Apparently, Waterstone's acquired Dillons mail-order internet site along with this excellent UK chain.
Chapters is great Canadian book chain that sells mostly English, but some French books.
Indigo is a rapdily growing chain that tries to promote itself as the bookstore with not only a great inventory but flair and style. They have a great store on St. Catherine in Montreal. I found their staff very helpful. Renouf sells Canadian and other political publications in Ottawa and Toronto. Renaud-Bray is a Quebec bookstore.