No one else use magento?
http://www.magentocommerce.com/
Its fairly easy to use and design for once you get the hang of it, lots of free and paid plugins. They have helpful forums but if you want their tech support its a boatload of money.
Theme forest has even started selling themes for it:
http://themeforest.net/category/ecommerce/magento
Good luck in finding the right one for you =D