The continuation of the solar cell and battery cost curves are pretty darn impressive. Costs halving about once a decade, for several decades, is pretty darn impressive. One more decade until solar is cheaper than coal is today, and then it gets cheaper (vast areas of equatorial desert could produce thousands of times current electricity production and export in the form of computation, the products of electricity-intensive manufacturing, high-voltage lines, electrolysis to make hydrogen and hydrocarbons, etc). These trends may end before that, but the outside view looks good.
That sounds promising for us (Australia). We have almost as much desert as we do coal!
A while ago I wrote briefly on why the Singularity might not be near and my estimates badly off. I saw it linked the other day, and realized that pessimism seemed to be trendy lately, which meant I ought to work on why one might be optimistic instead: http://www.gwern.net/Mistakes#counter-point
(Summary: long-sought AI goals have been recently achieved, global economic growth & political stability continues, and some resource crunches have turned into surpluses - all contrary to long-standing pessimistic forecasts.)