Nintendo has been talking about the physical design decisions made around the upcoming 3DS, including how the Japanese company made the 3D gaming console easier to open than the DS Lite but still avoided hinge cracking. According to Yui Ehara, from Nintendo's research and engineering department, the ice-cream sandwich style three layer stack is purposefully tapered so as to give a gamer's fingers somewhere to grip, unlike the slickly-abutted edges of the DS Lite. Meanwhile, there's also been work on new materials and coatings to boost durability.
For instance, while the tapering aspect helps you open the 3DS, it also increases the likelihood that, if dropped, all the impact force will be on a single point. To counter that, Nintendo used a new glass-fiber resin for the chassis, and rearranged the internal layout of the electronics to minimize damage. The new hinge design apparently took six months of prototyping, but Nintendo is now confident it will not only open readily but avoid the stress-cracks many DS Lite owners have complained of.
The buttons - now with a premium metal feel - and the circle pad have also been reworked for durability, while aesthetics get a look-in too; the battery cover now consists of the entire base plate of the console, so that the 3DS looks better to anyone watching you play. Meanwhile a new coating should mean that fingerprints brush straight off. They're probably not elements that most people will consciously notice, but then again that's arguably the sign of good design.