From a recent email to me from B2B Magazine:
"Each year, BtoB highlights 10 business-to-business Web sites that are particularly good examples of how companies can use the Web to communicate with customers. These sites turn out to be ones that do an exceptionally good job with the basics year after year, allowing visitors to find product and company information quickly and easily, providing a brand experience consistent with other marketing channels and offering a way to take the relationship to the next level. "
Check out B2B's 10 Great Web Sites.