I've used a few of these cheap LED ring lights:

http://www.amazon.com/SE-FL8824-Camping-LED-Light/dp/B000OP1AJ6/ref=sr_1_17

They're the best if you just want a lot of light. You'll probably want to do something to make them pretty or interesting. Use zip ties or wire to fasten a couple to your bike or whatever gear you're traveling around with. Mine have been very reliable. Every couple of years I have to replace the batteries.