Anyone who ever told you that a single company owning the market was a good thing had their head in the cloudsIn the latest edition of "why competition works," the Barnes & Noble NOOK e-reader is seeing one of the most impressive updates in a long time, and we have to believe that this update wouldn't be nearly as robust without Amazon's Kindle, Spring Design's Alex and Apple's iPad sitting beside it on the virtual shelves.

These days, consumers have lots of choices when it comes to buying an e-book reader