Show me the FIOS
The next thing that should be piped into my home is without a doubt fiber optic connectivity via FIOS or someone else. ComcastBusiness cable internet is proving to be quite satisfactory–paying extra for the business-class account means no b.s., no port blocking and English-speaking support if I ever need it (which, so far, I haven't)–but its bandwidth doesn't measure up to the raw speed of fiber.
It won't be solar-powered electricity, that's for sure. We had an engineer from Regrid Power out to do an evaluation of our roof and determined that it's unsuitable in almost every way; wrong orientation, wrong angle, too much shade, barrel tiles difficult to work with.
Our next likely option for energy-efficiency is replacing the rather old standard water heater with a tankless model.