Verizon has just released their new ringtone store. It is the the first ecommerce site entirely build with Flex i have seen so far. The site offers a great user experience which is way different from other ecommerce sites. Using transitions and dynamic data loading for building a shop frontend is way cool and i think that this a very good example which allays the fears of many other ecommerce sites that it may not wise to use Flex to offer a simple and fun making interface to your customers.

Have a look: Verizon media store 

Best,
Frank