I bought 3 of these and I'm extremely happy. I can ride safely 15-20 mph and still can see everything on the trial or road, including low hanging branches. http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IT
It's cheap to buy, very well made with cree q5 led, zoom and 3 settings. It also includes awesome mount and belt holder.
Runs on 3 aaa batteries, is waterproof and is made of aluminum.
Most cars slows down or stop when they see this light because they are confused seeing such a strong light moving a lot :-)
You can check my post in "post your hybrid bike pics" to see pics how well it works, or on Youtube http://www.youtube.com/watch?v=NlzGoV6BQQc