A thought on nanotechnology: considering that biological cells already have most of the capabilities of molecular nanotechnology, and that said cells have been undergoing natural selection for over a billion years, if something better were possible, it probably would have evolved by now. For example, I'd be very surprised if somebody one day makes a machine that's significantly better at protein synthesis than a ribosome is. I suspect that future nanotechnology will look a lot like today's biological systems.