Really, rechargeable batteries have improved, retain their charge much longer, and, according to Tree Hugger, are much less damaging than disposable batteries to the environment over the entire life of the battery. They are also a good price. It is essential that one gets the right batteries (most recommended: hybrid Nickel-Metal Hydride (Ni-MH) cells) and a good charger.
According to Metaefficient, here are the best rechargeable batteries:
1) Eneloop Rechargeable Batteries by Sanyo
2) Hybrio Rechargeable Batteries by Uniross
Here are the best chargers:
1) LaCrosse Technology BC-900 Alpha Battery Charger
2) Ansmann Deluxe “Energy 8″ Charger
3) Maha PowerEx “Ultimate Professional” Charger
Remember that rechargeable batteries must be recycled, rather than dumped. Luckily, DC has many options for this: Radio Shack at Eastern Market and other locations found at Call2Recycle.