I'm a huge fan of the book "Design for the Real World" by Victor Papanek. One of the things that he talked about is the importance of using materials honestly: not trying to pass plastic off as wood, using the given material to it's best ability (even if itis plastic).

I've always thought the Windows 3.1 to Win2K era were exactly that. The medium is pixels on a screen, the mouse and keyboard. And there is no artifice, it's just the bare essentials.