Take a look at http://www.solarbuzz.com/ for a chart showing retail prices of solar electric systems. The costs bottomed out about a year ago and have been climbing ever since, probably due to increased demand.

Bill Gross's Sunflower system from http://www.energyinnovations.com/ claims that it will undercut current prices by about 30%, but that's still going to be pretty expensive.

I considered adding a bunch of panels / batteries here a few years ago and guesstimated it would cost $20,000 at a minimum.  We have lots of sun so this area is considered "okay" but not "great."

I recall thinking "that's a car payment!"

Now, my electric bill, on a good month, is $200.  Perhaps it's time to check my math again...