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.)
Money is the straw utility function. There lies my hope in sunlight: if prices continue to fall down, it could drive fossil fuels (coal, oil, gas, uranium…) out of business. Geothermal energy looks cool, and nuclear fusion would be cooler still. But they seem more distant than sunlight.