I have a helmet mounted light that I love. Three out of the 4 employees in my office who ride to work this time of year use the same kind. It was made by GeoManGear but when I went to get a link for this message, I discovered they went out of business over the summer, which is really too bad. So all I can do is echo the advice to find a nice, bright, rechargeable light for your helmet. It lets you make "eye contact" with any driver that you think might be overlooking you - and gets an instant response!
The one I use is pretty heavy, and a little bit of a hassle to take on and off. In fact the light unit plugs into a battery pack that you carry in a pocket, so there's a cord running up my back and into my helmet. Not exactly elegant but worth it for the long battery life and brightness it produces. I put it on an older helmet, one that still has useful life in it but that I opted to replace with a better vented one for summer use. So instead of taking the light on and off, I just switch helmets for weekend rides.
edited to add: I also use these for side visibility - and because they're fun: http://www.rei.com/product/774213/ni...ke-wheel-light
Last edited by ZenBiker; 11-01-2012 at 03:41 PM.
Road bike: Specialized Ruby Comp (2011)
Commuter: Salsa Vaya (2012)