I don't think that responsive web design is a fad. No way. I don't want to download an app for every website that is out there. I want to simply visit the same sites that I do on my desktop and receive the same content in a way that is pleasant to view on the device that I'm using.

This isn't a Web 2.0-like design style that comes and goes. I'm sure the techniques will evolve in time but I can't see us ever going back to fixed width layouts.