This is a discussion of things yet-to-be-invented.
- Cheap Fusion energy: incredibly valuable, and currently just over the horizon (as it's been for decades, now).
- Room Temperature Superconductors: also incredibly valuable and may be just over-the-horizon. Would enable cheaper electric distribution, dense energy storage, smaller & more powerful motors, faster/cooler semiconductors.
- Artificial Diamond as a building material: This would be incredibly useful. Diamond is the hardest & most durable material, has the highest tensile and compressive strength, is the most transparent, and has the highest thermal conductivity of any solid. See Diamond (Carbon).
- Stasis Fields: Nothing in physics prohibits a region from having a slowed (possibly stopped) passage of time. See Larry Niven's Known Space stories, or Vernor Vinge's The Peace War and Marooned In Realtime. I'd love it if a restaurant chef's freshly prepared dinner could be opened at any time in perfect condition, ready to eat. Or if an accident victim could be bobbled for transport to the hospital.
- Direct human-computer Interface: The ultimate I/O device would be high performance direct interface to the mind, useful for augmenting memory or senses, useful for controlling complex things, invaluable for virtual reality. Possible in principle, but I have my doubts due to the volume of needed I/O points and the complexity of the brain.
- Affordable Robotic Artificial Intelligence: A humanoid robot with sufficient intelligence to perform most simple human tasks such as housekeeping, organization, and building things. In principle, this could make the people of the world very rich. Problem: see Robots and Slavery.
Damn, I wish that was possible:
- Faster-than-light travel: God said, "Thou shalt not exceed the speed of light." The universe is far too big unless we can find a hole in this one. Of course, it has to be cheap enough to be useful, just like in a million or so SF stories.
- Cheap, Fast Space Travel: We really need this, because without it, planetary surfaces are simply too expensive to frequent, and interplanetary travel takes a very long time. Even at a constant 1G, travel times to and from our own Oort cloud are of the order of a year. Don't even think about interstellar travel. There's a corollary: Artificial Gravity. Whether we need high accelerations or simply a convenient place to stand (see a zillion SF movies), we'll need gravity control. Doesn't look reasonable to me, however. Another corollary: Reactionless Drives. Without a non-polluting way of generating very high thrusts, most planet based civilizations are not likely to welcome a spaceship in every garage. But God seems to be stuck on this conservation of momentum principle. Even in space, a lot of mass gets thrown away accelerating from here to there. Very wasteful. Lots of luck on this one.
- Time Travel: Sorry, folks, but traveling back in time just ain't gonna happen. Larry Niven said it best: "If the universe of discourse permits the possibility of time travel and of changing the past, then no time machine will be invented in that universe." It's simple cause and effect. If you can travel back and change the past, the present is unstable. The only stable reality is one where traveling back in time never happens. Sorry, Terminator.
So, what inventions to YOU want? Or know can't possibly happen?