Savonius are good.
Imagine a tin can stood upright, cut it in half down the middle as though going to make a barbeque out of it.
Slide one half along the cut line so () becomes
(
)
but still touching and and weld a shaft between the two edges.
This then sits on top of your generator motor, or use a pulley belt.
Works in very low wind, does not need to turn to face the wind and can be put almost anywhere (depending on size).
You may have seen a similar thing outside your local shops, where they paint the logo's in two colours so it flashes as it turns.
Check out this US website where the guy gives full diagrams and reckons to do the job for less than $100.
http://www.motherearthnews.com/library/ ... uper_Rotor