Earlier, wrote about the differences between a CIO and a CTO. Doug Kaye offered another:
CIOs are primarily concerned with how their company consumes and applies technology. CTOs are primarily concerned with how their company creates and exports technology.
I think the producer/consumer contrast is quite appropriate. Of course, in the process of consuming, CIOs create new things and in the process of creating, CTOs consume technology, but coupled with the other statements in my earlier post, I think this has the right context and serves as a good summary.