Digital cameras need a lot of electrical power to perform their multiple functions.
That's why your best choice would be to use rechargeables. There are several types of batteries ranging from the disposable type AA alkaline to Lithium Ion batteries that are 3 times as powerful, possess excellent cold weather performance and have a shelf life of up to 10 years.
Batteries are rated in milliampere-hours (mAh). This tells you how much current a battery can supply and for how long. The most common rechargeables are Nickel Cadmium. (NiCd) and Nickel Metal Hydride (NiMH) of which the latter are more powerful. They last through hundreds of recharges, yet they will lose their charge slowly if not in use. Obviously rechargeables are cheaper in the long run, but if you only take the occasional picture use lithiums which hold their power for years. However if you do a lot of shooting put rechargeables in your camera and carry a spare lithium for emergency use.
If your camera will not be used for a long time, remove alkaline batteries as they may have the nasty tendency to leak caustic chemicals.