Light and Motion Solo Logic NiMh - got it from chainlove like it says above, 390(!) lumens for under a hundred bucks can't go wrong. The only issue was the included helmet mount didn't ship so i used the bar mount - a little freaky on log overs, ramps, ladders etc. as as soon as the front wheels lifts, the light is gone - helmet mount is on it's way as CL /SAC customer service rocks!
This light is back on chainlove right now for anyone interested. The description specifically states that it does not include a helmet mount though.