As mentioned a friend had a company give him a quote for a solar system, here are the numbers. (Best I can remember)
The ideal roof angle is 35 degs his is 22.
Cost equipment and installation. $51,000
Pay back 5.5 years at $0.73 per kw/h. This does not take into account, taxes (property, income), insurance, and interest if panels are financed. The $0.73 per kw/hr is not written in stone and can be changed.