Alley Bate wrote:Like most anything, It depends
HAWT - horizontal axis are generally most efficient if put in optimum conditions, VAWT - vertical axis generally have an advantage in swirling, gusty, low to the ground conditions and to most eyes look cooler.
Blades cut from pvc pipe or plastic barrels are popular for first efforts with treadmill or servo motors, this is the route I'll probably take for my first effort.
If you'd like to carve your own from wood, depending on how fancy you want to get, do a web search for NACA profiles.
Serious consideration must be taken to protect batteries from overcharging when adding wind to a system.
If you haven't been yet, check out http://www.fieldlines.com it's an awesome diy energy forum especially in the wind dept.
Looking forward to seeing what you come up with!