K, I have a CygoLite Night Rover NiMH. http://www.cygolite.com/2-Products/8-RoverNimh.htm When it is on high it lights up the road like a car. The battery fits in the bottle cage. I don't like having to give up a bottle cage but I found out that in the cool evenings I don't drink like I do in the heat and one bottle seems to be plenty for a 20-25 mile ride. It was such a cool experience. I highly recommend it. It will also allow me to get more miles in each week.

onimity, I am thinking about a headlamp so I can see my computer and HR monitor...but it was also kind of nice not staring at them all the time.