As there must be Rules at the Drupalcon Munich as well, I've had a Rules session together with Richard Jones from i-KOS.
Head over to the session page for a summary and find the slides attached attached to this post as well. Moreover, you can find all the screencasts we've used during the presentation here as well. It's a real Drupal commerce site we've been using in the session to show how Rules can be used to solve real life problems.
1 - No VAT for certain products
2 - Discounts for products that are not belts or bags
and then to make it work the same way years ahead
3 - Subscribe to back in stock notifications via Flag module.
4 - Notify me when something needs review with Workbench moderation
6 - Let's do promitions, but only on Monday please!
7. Message users if they abandoned their carts
8. Log user communication with the Message module