We were surfing around on Lab126's website and we saw this explanation of Amazon's vision for its Kindle line. (Lab126 is the Amazon subsidiary developing Kindle products.)
We like the simplicity of this slogan: "To make available in less than 60 seconds every book, ever written, in any language, in print or out of print; and bring the same ease-of-use, deep integration and superior selection of content to movies, TV shows, music, magazines, apps, games, and more."
It's good to have a simple slogan. It helps you think about making tough product choices.