Yeah the original Sega Master System had a very unique design while the second was just a bit bland (I only own the SMS II however).
When I think about console design, most systems are just, blah...either a front loading or a top loading box. Nothing to special from any company really. I mean there have been some sleek designs but I don't think any system yet has Nailed it. The two closests for me would be the Duo RX, which I think is perfectly designed and very nice how it evolved from the original Duo. Also the design of the Playstation 3...which looks very similar in design to the Duo RX. The PC-FX was also a nice unique design as far as console systems go.
But, by far the sleekest, hottest design to me is the PSP. I know its a portable but it is much more than a mere portable. It is one of the nicest looking peices of Tech hardware to come out in some time in my opinion.