If you own property that has access to a stream or river, and want to produce your own electricity, then Hydropower should be your first choice. The cost of equipment is lower, and the kilowatt per dollar return is much better than any other alternative energy source.
The most important element to have when producing hydropower is what is called "drop". The greater amount of change in a stream's elevation, the better it is for producing electricity. A small stream with a good drop is better than a larger stream with a small change in elevation, because the turbine needed to tap a small stream is smaller, easier to install and less expensive.
Hydropower often produces an excess of power, especially with direct AC systems. This excess can then be used to heat your water or warm your house, for example.
A recent post at Alternative Energy Blog pointed out that villagers in Vietnam are using $20 "Pico Hydro" turbines (300W and 500W) to power their homes, because it is cheaper than buying power from the grid. Apparently these turbines are not available in the U.S. — the only web site selling them is in Nepal.