Now that rechargeable batteries come in the same size as normal batteries, even AA and AAA sizes, there's no excuse not to invest in batteries that could last you anywhere between 100 and 1000X more than your regular throw away varieties. It's good for the environment and your wallet in the long run. Duracell and Rayovac sell battery rechargers that make reusing these guys as simple as a 20 minute plug in.
Nickel-Metal Hydride Cells
While this sounds like the beginning of that song about the Periodic Table of Elements, it describes the chemistry behind how we now have rechargeable batteries. These hybrid Ni-MH batteries can hold a charge for months at a time, which means you can leave them in flashlights and they'll work as sporadically as you use the silly thing. It doesn't matter whether you'll be using the batteries for the battery drainers like PSPs or digital cameras or slower energy users like smoke detectors or remotes, the rechargeability of the battery and how well it works doesn't differ.
