While selling directly via the web has higher margins, it also sacrifices volume since most retail is done through bricks and mortar.....as Dell's recently strategic shift in the consumer space indicates. This is especially true for consumer hardware.
I think Amazon should seriously consider selling the Kindle decive through traditional retail channels in addition to the web strategy.
On one hand, they will have to give up considerable margin to the retailer...on the other hand it will increase volume. and if Amazon makes money on the actual selling of the books....the increased volume could make up for the lower margin.
An additional benefit is that it will drum up traffic for the website as these Amazon Kindle displays in all the retail channels acts as advertising for Amazon.
I think this is the smart play. With somethng as personal and expensive as an e-reader, the consumer really needs to experience it before buying it.