Doesn't make economic sense in Kentucky. Threw some numbers in an online calculator, and with a 2 kW system (cost about $8000 to install) you'd save about $229 per year in electricity at current prices. That's a 35 year payback period.
Large non-residential installations are way more cost effective (about $2.20 per watt vs $4), and in states with more sunshine than we have and/or higher electricity rates, these large scale solar plants are economically competitive.
As for home, even in Phoenix, AZ that same home system has a payback period of 21 years. Maybe reasonable if you have the cash to put out and are going to be staying in the home for a long time. California is really the only state where is makes sense, and someone above was pointing out negatives about that. If you want to do it for ideological reasons, or if you want to make a long term investment especially if you anticipate electrical costs going up, it could be worth it in certain states. No economic incentive to do residential in Kentucky.
edit: My friend who used to work in the industry (non-residential mostly) pointed out that Kentucky gives a $500 credit and federal government a 30% credit on remaining cost. So that would drop installation cost to $5250, and the payback period to 23 years.
