Don't forget that the lifespan for the power inverters for solar is about 10 years.  About the time you recoup your initial ROI you'll have to invest about 30-40% back into it AGAIN to replace them.

Unless your state offers a tax incentive or rebate you will be VERY hard pressed to find any form of solar panel ROI unless you're willing to wait 15+ years.

I live in Florida (which is a prime spot for solar) and I pay $0.14 to $0.16 a kwh (post taxes).  The best ROI any installer could show me was about 16 years and a warm fuzzy feeling for reducing my carbon footprint.