Many upscale product brands are entirely constructed out of flash. nike.com is entirely flash, for example.
But Nike's site downgrades gracefully for those who don't have Flash installed. The Store, for example, is offered in both Flash and HTML. This is how it should be done, and proves that not everyone uses or has Flash installed. Otherwise, Nike wouldn't bother offering their site in two versions if Flash was a standard part of the WWW.