As a high school senior starting college next semester, I'm doing a lot of looking forward for careers that will explode in numbers and usefulness. Quantum computing seems, to me, like it will dramatically change the world in the next 10-20 years, much like the PC revolution did. Am I wrong in this assumption? Would it be unwise to major in something as specific as computer engineering and quantum physics?
Don't think you'd be required to know everything about quantum physics to program a quantum computer, just like you aren't required to be a electrical engineer to be a decent programmer. But if you are talking about a lifelong contribution to research, and you are going for a PHD then there is nothing unwise about that.
Someone will build the first quantum computer. I highly suspect that that person will also have to have a strong knowledge of quantum physics. Either way, it seems like a promising career field unless the theory for a quantum computer suddenly becomes impossible (which doesn't seem to be the case).
Mobile will dramatically change the world because smart phones will be the first computer which billions of people around the world will own. It's largely just getting started because prices for entry level smart phones are dropping but still not quite cheap enough that they are within the reach of most people. This trend will be interesting for quite a long time and game changing apps will be both global and local. In other words, an app which is highly beneficial for farmers in x region of Africa may be unhelpful to farmers in x region of S. America because of differences in language, culture and the ways in which these economies run in each of these regions.