Cygolite 170 is $55 at Amazon. Close enough.
http://www.amazon.com/Cygolite-170-USB-Rechargeable-Headlight/dp/B005DVA592

For me I strongly prefer a cell phone style, plug-the-whole-thing-in-to-recharge-it setup than something with separate batteries to buy, recharge, and lose track of. The only negative thing I've ever seen said about this line of lights is that the USB hole sometimes opens to water but I've never found a report of one actually being damaged by the rain. I think this very straightforward solution should do very strong in the 2012 $50 headlight sweepstakes (except for that extra $5 bucks, I guess)