Which of these developments would be most likely change our lives the most?

hmm, you can't really beat The Apocalypse in terms of life changing events.

 

I heard 20010 or 8 they hope to compleat as we Techanchians call a BIg ass laser that is gogint to fuse two hyrdon atoms...or we could just claim we onw the sun thus controllying fusion

 

Superconductors!

 

Has to be nano-tech for the simple reason that it gives us an entire new tool box to work with.

 

Well, I think that superconductors at room temperature is feasable and will happen, it will change all of electronics.

I reckon that Fusion is also a good possibility. As far as I know the "Big Ass Laser" also known as BAL has already been used to make fusion happen, it is just impractical on account of using more energy than you get out, and there being some hassles with how to get more tritium and deuterium in and the products of the fusion out, whilst keeping the whole reaction going.

 

I chose commercial nanobots, just think of the uses of such a thing ! (i mean ... almost everything would be possible!)