Bookshelf

Barnes & Noble: This is the place that cleaned my pockets when I was in New York. It's an evil place, beware! ;-)
Amazon: Another evil place that I stay longer than I should. I got bankrupt because of this devilish site
Alibris: If you've got more money than you can spend, come to this 2nd hand bookstore, and make sure you have your Platinum card ready for use!
Alyson Bookstore: Try small literay publishers, you might find some surprises there!!
Firebrand
BookWeb: Anything you want to know about American booksellers.
Bookwired: It includes categorized listings for booksellers and publishers, books reviews, book events. You can download an entire book (an entire library, if you wish) directly to your computer absolutely free from their Reading Room.
A Clean Well-lighted Place for Books: A place to look for alternative reading.
The Internet Book Shop
Little Sister's Art Emporium
Sisterhood Bookstore: Sisterhood! Hey, doesn't that give you a hint. This is a bookstore that prides on its gender and racial equality in their selection of books.
InsightOut BookClub: Whether you're in or out of the closet, this is definitely your cup of tea.