I recently posted a page to Ubercart.org titled, Why use Drupal for e-commerce?. In it I made some observations about Drupal and how it is the perfect platform on which to base an e-commerce site. All the things we wish other e-commerce specific systems would do (or that we have to hack to get done) Drupal does out of the box. Feel free to give it a read and offer up any feedback here.