Dinotte 200l AA. I just posted its attributes in the thread- Need lights for $100-$200. It produces 200 lumens. If you point it straight ahead (you don't want to do this, angle it a bit down like all bright lights) you'll blind oncoming riders. It's not bright enough for technical stuff at night, but for XC or road cruising (not descending) it's good.
ive had good luck with my trailtech 13w system NiMH battery so far http://www.batteryspace.com/index.as...OD&ProdID=1395
i got it from batteryspace rather than from trailtech as the helmet mount from batteryspace seems better, actually has a strap. from reports the Li-Ion battery version seems to have had issues with burning out the switch though