The best way to protect the chamfered edges are with a skin that covers them.
I use the digiskin full chamfer metallic series skin, and it works well on the edges (although it leaves a fraction of a millimeter of the back unprotected on the edges.)
Sometimes, I use a case too for extra protection.
Cases alone may not protect against scratches since dust and debris rubbing between the case and the phone may cause damage. Even silicone cases can cause damage. I used a incipio dual pro on my old iphone, and it left some marks on even the screen (although they were microscopic and could only be seen at an angle in the light).