> I expect that many things which look promising today will be complete
> duds five years from now, and in 20 years the big news will be coming
> from something we haven't even considered today.
We might not be considering it, but it's there already, at least as laboratory curiousity. Also, despite acceleration, technologies still take time to permeate the market, and be it only due to human/market attenuation. We can make a long list of candidates: space, biotech, nanotech, computation, etc.
Some of them might be duds. But not all of them. Also, we're not asking Joe Sixpack for comments here, but early adopters. We _are_ early adopters, right?
In fact we should indeed make such a list, publish it along with predictions and freeze on several websites to reduce its chances of going away. No need to aim for 20 years: let's try 5, 10, 15.