The Light and Motion Urban 300 is a great, great light. It charges via USB which, at least for me, is pretty much ubiquitious. The light, itself, is amazing. I ride through a park which is pitch black and this light throws enough light to get me through the park easily. I would highly recommend this light
Mid-Atlantic Bike Commuting 
I have the helmet mounted vis 360 and I agree that they make great lights. The USB feature in particular is a nice feature ensuring the light is always at its brightest.