Here is my view on the most influential future technology (gadgets) that will change our lives to the better.
The first and basic technology we need is a good way to accumulate and store the electric power. Now we have very weak accumulators in our mobile phones and laptops. They can store up to 5-10 Ah (Ampere-hours).
We have a little bit stronger accumulators in our cars but they are too heavy to carry in our pockets. They can store up to 50-100 Ah, maximum 1000 Ah in special electric cars.
Unfortunately, there are not at all very big and strong accumulators capable to store millions of Ampere-hours. We need them to collect and save energy from our huge power plants like nuclear and hydro plants.
One possible solution for this problem could be fuel cells and hydrogen energy economy, when energy is saved in the form of hydrogen at special safe houses. Pure hydrogen is very dangerous because it can explode easily, so we need some polymer or other methods to make it safe. And this is problem number one. When we solve this we'll get plenty of clean energy because the output of burning hydrogen is pure water. The chemical reaction is simple: 2H2 + O2 => 2H2O + energy.
The second technology of the future is a nano-assembler. It's a tiny device of nanoscales which can assemble other devices and itself by the program. It will take atoms or simple molecules and put them together in a predefined way. It will be a real molecular factory which can make everything to satisfy our needs, even food.
It sounds unbelievable but we are absolutely sure that it's possible, because in nature it does work perfectly. All living beings including us construct themselves from organic molecules following the program in DNA.
The most difficult thing is to create the first nano-assembler and then it will assemble tons of them. But it might be a problem if they get out of control. This 'grey goo' could destroy the whole biosphere of Earth in one day.
The next amazing technology is an avatar. These are artificial bodies like in the famous movies "Avatar" by James Cameron and "The Surrogates" with Bruce Willis. Just imagine that you will be able to connect to them via the Internet, feel what they feel and act as you are there. So the world will become much smaller. You can physically live in one place, but work or have fun in other long distance places.
And the next technology but not last is very fast learning at the speed of light. If scientists find out how to read and write memories in our brains, we will learn anything we want easily. We will just download new knowledge or skills from the Internet, put them into our brains and teach ourselves. When it will be possible, I want to download French and Italian languages, new programming languages and Taekwondo.