I just bought an SSC 900 lumen headlight/ bicycle light from Deal Extreme for about $45. It is EXTREMELY bright and the installation took all of about 30 seconds. If you have the grab handle, this is the only way to go! Here's the link and a video:
http://www.dealextreme.com/p/ssc-p7-...-4-18650-50947
I've have a couple of the flashlight versions of this light and not only are they super bright, they are also durable and well made. This one comes with light, head strap (if you want to use it that way), two rubber straps, battery pack, and a wall charger. What a great deal!!