Rechargeable batteries are a lot cheaper in the long run. I use them in my GPS's and radios, and camera strobe. Make sure you get one of the fast chargers or else you cold be looking at as much as 14 hours to put a charge on your batteries. I picked up a Duracell 15 minute charger with 6 NiMH batteries (4AA, 2AAA) for $30 at a wharehouse store. One caveatt if using them for your headlight. Alkaline batteries have a nice rundown curve (as well as put out 1.5 volts each) so your light will start off brighter and dim down as the batteries die. The rechargeables are only 1.2v, but stay constant longer, then suddenly just die.