Flashlight. Doesn't get any simpler. Look around here, there are threads. Personally my recommendation is a P7 flashlight with 18650 battery and chargers and a mounting block. The whole thing is around $60 and it will absolutely be as much light as anyone really needs on the street. If you check threads around here though you'll find recommendations for AA powered flashlights that can use rechargeables and will probably be able to set you up for $30 to $40.
Don't go too cheap. A lot of us have spent way more money buying cheap crap that didn't work than we did in buying the better stuff that did.
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Work: the 8 hours that separates bike rides.
Last edited by ItsJustMe; 08-30-10 at 01:33 PM.