Even if you don't like the time it takes to pay off a PV system do look into solar water heating. The initial investment is much smaller and the payoff times much shorter. There are areas, like the far north where freezing is an issue eight months out of a year, it doesn't make sense without making the system complicated but for much of the south and west even very basic systems can pay themselves off in a very short time.

PV isn't the only game in town.