I seem to recall an article recently about a scalable photonic quantum computer . . .
Feynman/Drexlerian nanomanufacturing can do much. It can improve all technologies of today from ten to a thousand times in any number of properties. It would make the industrial civilization of today look like the stone age; that may not describe the technological revolution enough. If you consider that just changing the geometries or the atom combinations changes chemical properties, then you can see that by really taking control of those atomic alignments, one can make an astronomicaly more advanced technological base. Considering that life is nanotechnology, one can see that one can do this astronomically more advanced technological base for the price of growing potatoes. And yet, even Feynman/Drexlerian nanotechnology could be turbo-charged or even replaced all together!
Quantum computers could lead to quantum technologies. What are these quantum technologies? Quantum dot technologies which can make for solar power of like 90% photon to energy conversion rates. How about Star Trek teleportation? Alternative chemistries! Control how photons interact with electrons and protons, and one could make alternative chemistries materials. We're already seeing cloaking technologies develop. I've actually mentioned all this before; the youtube above is one of the first open statements to the affect. Much like nanomanufacturing, we probably don't even know all the technologies that can come out. Obviously, quantum computers can burry classical computers in computation speeds and solving problems that classical computers never have a chance to solve. Of course, what's always left out is the affect of all this on mathematics; what mathematics problems can be solved in no time flat?