I like to calculate this stuff out for fun.
You need 20 200 watt panels to save $75/month at 5 sun hours and .14/KWhr.
If your inverter, charge controller, wiring, mounting, and labor were all free, I calculated break-even on the order of 150 months, or around 12 years, just to pay for the panels.
I bet a complete system would calculate out at 20 to 25 years break-even at .14/KWhr. If electricity rates rise at approximately the same rate they have been, maybe you are back down to a 12 to 15 year payback, assuming zero maintenance.
Now just for fun, if you had invested 20 grand into gold in 1997, you would have close to sixty thousand dollars today. $40,000 profit would pay for 44 years of $75/month electric bills.
If you're trying to save the world, have at it, but if you're trying to save money, there are better ways than grid-tied solar in my opinion.