Treehugger's Lloyd Alter recently attended the Greenbuild International Conference and Expo in Boston. He describes Agriboard Structural Insulated Panels (SIPs) made by Agriboard Industries as

perhaps the best thing I saw

We previously covered SIPs and how they are made.

In constrast, an Agriboard SIP:

... uses wheat and rice straw that is normally burned or ploughed under, and builds it into a panel that delivers R-25, not as good as a styrofoam SIP but pretty good and in a form that gives you a tight envelope.