It really depends on what the batteries are going to be used for. If I just need a set of batteries, say, for a remote controll at work, I purchace off-brand alkalines. If I need a pair of AA in a pinch, say for my digital camera, I purchace Rayovac Alkalines. Look on the battery packaging to find out the available current per unti time, usually listed as amp/hours. The higher this number, the more energy is stored in the battery.
Most of my home electronic battery needs are taken care of with Nickle/metal/hydride rechargeables. They resist developing a "memory" if charged before complete depletion. They cost a bit more initially, but save me bunches as they can be recharged a thousand times or more.
If I need a battery for something that is rarely used, but important, like a smoke alarm, I go with lithium batteries as they maintain their original charge for up to ten years. All other kinds of batteries discharge through themselves over time and have significantly shorter shelf lives. And, lithium batteries currently have the highest energy/density of any batteries available to the public.
Some things to know about batteries;
Batteries work by storring an excess of electrons on the cathode, with a lack of electrons "often described as holes in electronic jargon" on the anode. This creates an electrical imballance as all things in nature try to maintain a state of equillibrium. Some type of acid or electrolyte is housed in the battery structure between the anode and cathode. You've heard of battery acid. This is sulfuric acid in car battery, or lead/acid battery. The electrolyte allows electrons to flow through it from the cathode to the anode, thus equallizing the charge between the two. When both cathode and anode have the same electrical charge, the battery is depleted. To recharge, a strong reverse charge is applied by a power source, again stripping the anode of elctrons and re-depositing them on the cathode until the battery is again fully charged.
This is called an electro-chemical reaction. Most batteries are highly susceptable to temerature change. A car battery loses its ability to deliver power as the temperature decreases. That's why the car won't turn over when the temperatures dip to the - degrees F. range. It has nothing to do with metal contraction or thick oil at lower temperatures. I've proven this concept many times over the years in my own cars. When everyone else was unable to start there vehicles, mine turned over like it was a hot summer's day. My secret, put a cheap electric heating pad around my battery at night. I try to let people know this trick so that they don't have to invest 100's of dollars in expensive block or radiator heaters. But most people just look at me funny.
Also, if you are going to use portable devices, such as cameras and such, in cold places, keep them inside your coat, to keep the batteries warm. Some batteries such as lithium and nickle/metal/hydride are less susceptable to temperature changes, but it does affect their useful energy output.
Hope this wasn't too much info. Oh, and a bit more jargon for you; Rechargable batteries are called "primary" batteries in the industry, while non-rechargables are called "secondary" batteries.
You now know more abnout batteries than 90% of the population. Don't you just feel special?
Seeeeeeya; Goodweed of the North