I think there is a lot of hype around Node - just as there is about NoSQL, Big Data, and the latest trendy javascript framework/library. However the vision of a single language that can be used in the front-end and back-end for web applications is a pretty powerful and seductive one in my opinion. Node development is pretty much in its infancy and I hope it keeps growing and maturing.
In any case I very much agree that the right tool has to be chosen for the right job. And the right tool is a function of many things - both technical and non-technical - the most important of which is the (business) bottom line.