If you're talking about AA batteries, look for those that are 2500mah. These have the highest capacity so should last much longer than the cheaper ones.
Don't know where you live so not sure what brands are available in your area.
When you do buy these batteries, make sure you buy a recharger that supports such high capacity batteries, otherwise standard ones will only do half recharge... typically upto 1300mah.
There are 2 new types of NiMH batteries on the market.
-They have a 12 month shelf life and higher capacity.
-They work with any standard NiMH charger.
-Costs are higher than standard NiMH but should go down. Shop for price. I was surprised that Ritz price beat Circuit City.
EP, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS