To say, as Sam and Tim both do, that REST is important is like saying the fan in my laptop is “important”. There’s really nothing to discuss about it. RESTful services are fundamentally critical to the continued evolution of the Web. It just is. You just need to do things in a RESTful way. Period.
REST is just a starting point. What’s more important going forward is the framework which permits us to reason about REST extensions and other changes to the Web (or portions thereof).