The alpha release of a new e-commerce package for Drupal sites was launched recently. The module is called Ubercart. You can read reviews here and here, and see the module live in action here.

I am somewhat familiar with the "old" e-commerce package, but initial feedback about the Ubercart e-commerce package indicates that the new module is promising. For example, the developers have seen to it that Ubercard is more user-friendly and that there are fewer clicks/steps for a customer to buy a product; products can also be purchased by Anonymous users. At any rate, here is the comparison page which you can bookmark for future reference about Ubercart.