If I were looking at lights less than $100 I'd seriously consider the Cygolite Hi-Flux 100. It uses 4 C batteries and has a run time on high of 25 hours.



A poster on another forum replaced his Cateye EL-500 with this light for riding brevets and says the Cygolite is much brighter and plenty of light for night riding.

Cygolite says its LED light is equal to 10 watts of halogen.





You can find it online for about $70. http://www.cygolite.com/2-Products/3-Hiflux100.htm