I'll throw up another recomendation for NiteRider minewt series. I am running the minewt 100 wich is now a 350 model for the same cost. It incredibly bright has a great flashing mode, recharges with USB wich is great for a commuter. they have a great warranty. and the company support cycling events by offering free charging and cheap rentals, and on site warrenty swaps at 24hr events (thats HUGE in my book) Its right at $75-$100 depending on where you order it. I can use it all week commuting on one charge

oh and good warranty dosn't mean they break often, but were cyclist we fall, we drop stuff, were hard on things, nice to have a company that knows that and willing to replace it.