No one has said it better... ever.
Apple, the design juggernaut that they are, put together this amazing video that takes you through what it means to try and create GREAT design; not good design, but GREAT design. Apple has done this better than anyone, so they have the right to write the book on. Most people take it for granted how relentless you have to be when designing, and how many no's there are before there is a yes, I love this part of the video. What really sets it off is that even the video describing what great design is, is great design.