Upgrade

I recently spoke with a client who has an e-commerce website built with Drupal 5 and Ubercart. I sat down to write the top 3 reasons to upgrade your website from Drupal 5 to Drupal 6. Since Ubercart for Drupal 7 is in Release Candidate3 status, it's not ready for production use.
 
1. Many of the features you are asking for come built in with Drupal 6
- one step account sign up
- auto fill of billing address at the checkout