http://www.amazon.com/Vetta-TSL-C-Fl...owViewpoints=1

I hardly ever see this tail light recommended but it is the best value for the money IMHO. 4 AA's and 20 LED's for around $50 is a lot of light. I have used it for 2 winter of night riding with zero problems. Using the Vetta on high or low in conjunction with a Cateye LD600 in flash mode is an awesome combination. Vetta flash mode is powerful also. Some think the Vetta blinks too slowly but I think that it is effective at it's brightness level.