I use a Princton Tec Apex headlight which I have attatched to my helmet. I prefer to use helmet lights as my main light, that way the light is always with me, wherever I turn my head thats where the light goes. The one thing I've noticed is that a lot of drivers get a little bit confused or "shocked" when they see a very bright light on my head I think a helmet mounted light has a big advantage over a handlebar mounted light ,not just for illumination but also if you have an emergency or breakdown at night... it's nice to have your handes free when trying to change a flat tube in the dark.