Storage and back-up systems are going to be very important given the sun doesn't deliver that much energy to any one place at a time. The solution would be photovoltaic panels and solar heating troughs over huge tracts of land along with a direct-current transmission backbone to send that energy efficiently across the nation..Imagine a future where solar panels pave the desert between Phoenix and Los Angeles and consider whether that be worth the ecological footprint?
We know lot that can be done with the existing solar technology today that would reduce our dependency on fossil fuels. Solar thermal plants are assuredly one part of the solution, but there is the water conflict which cannot be overlooked. In short, this alternative has the potential to create a great deal of electricity--now--and I hope the policy catches up and we integrate it into landscapes in a way that doesn't add pressure on other limited resources.
Also remember that our energy needs exceed what solar power generates. So while I think we should be powering our cars and appliances on electricity, we must depend on many sources for a more sustainable future. We will still need combustible liquid fuels for shipping and air transportation. Personally, I continue to be interested in plant based biofuels. There is no better solar panel than the leaf of a plant. Alone it will not be the only answer, but may eventually contribute to a significant percent of our energy budget.