A free, worldwide membership community with the goal of "making the whole world a library." Register the books you read and pass them along - you can follow their travels through their BCID numbers. Set your books free, and find new ones for free, too!
Go to any small, independent bookstore and you are likely to find the most current issue of the Booksense newsletter. Each month, a list of book recommendations is compiled, based on recommendations from independent bookstore employees. There are also specialty pick editions that focus on a specific theme or genre. These books might not all be on the best seller lists, but they are wonderful books nontheless.
I hype this site pretty often - it's an e-mail book club (actually, a dozen of them, and you can sign up for as many as you want) that makes weekly selections and e-mails you daily excerpts. It's a convenient way to sample books, and I've found a lot I wanted to read further after getting that taste.