Check out LED by LITE is an amazing lighting solution for your bicycle. They have 360° visibility and are bright and very visible. They were also invented by some great people here in Utah!

KSL article Utahn’s bright idea making streets safer for cyclists November 2011
Visit their website at www.LEDByLITE.com
For about two weeks use the promo code "local" to get 50% off if you live in Utah.
Enter to win one for free on facebook.

I bought a set of these lights, and the inventors came to deliver it! The daylight and my camera didn’t do the lights justice. They are really very bright. They have 180° visibility, turn signals, power saving modes, and a few more features.