I think it's more then just a good case design. I think people actually fell like Apple is listening to them. The USB and Firewire ports on the front are a god-sent for those of us who use digital cameras on a semi-frequent basis or have people handing us various types of media (card readers, digital cameras, keychain storage etc.)
The design does continue on with Apples commitment to superior design, but also take the business direction.
If anyone had the "luxury" of trying to "sell" an accounting department on a blueberry G3 tower... you will know they didn't fit into the corporate world...