When developing software it is a fact that we spend way to much time and effort on implementing things that will only be used sometimes, rarley or NEVER! There are several studies covering this. One such example is the famous survey by The Standish Group in 2004.
The Agile community are trying to solve this in SCRUM by an approach of really focusing what is important for the customer right now, instead of the approach of focusing on everything-at-once. One examplary example of a product that focused only on the features used always and/or often is the.. iPod!
Furthermore, and speaking of iPod, I was attending on the Öresund Agile conference in Copenhagen (arrange by my company: Softhouse) when there was a session with Andy Hunt showing this fabolous clip of what how microsoft would (re)design the iPod package if they would do it their way:
Are you building an iPod package, or are you building the microsoft package version of the iPod in your project?