American Library Association's Notable Books
A yearly list of "very good, very readable, and at times very important fiction, nonfiction, and poetry books for the adult reader."
http://www.ala.org/rusa/notable.html

Bestseller Lists 1900-1998
Lists by decade of Publisher's Weekly bestsellers provided by Cader
http://www.caderbooks.com/bestintro.html Books

New York Times:  Books
Bestsellers lists. View current top five bestsellers. A free registration will give you the complete current list.
http://www.nytimes.com/pages/books/bestseller/index.html

Publisher's Weekly: Bestsellers
View bestseller lists and news about author and best selling books.
http://www.publishersweekly.com/bestSellers.html