Down Low Glow
 

I saw a bike with a neon bulb on the bike path the other night and it was really impressive. The light is somewhat bulky and expensive but the glow it puts out is amazing.

http://www.rockthebike.com/lights/downlowglow

I can't afford that light myself but I tried out another product that I bought for $6 and puts out a whole lot of visibility bang for buck. These are valve stem covers with led lights and batteries built in that have motion and light sensors so they only emit flashing light at night when the wheel is moving. The light is quite bright and really accentuated by the rotation of the wheel.

http://www.jpcycles.com/productgroup...F-596D9ED8E281