Like CalHunter said volt test the batteries. Most times they are daisy chained, hooked in series, so the end voltage isn't 1.5 volts but 4.5 volts or more. If one battery in the chain is bad or weak the whole chain is bad or weak.
I use nothing but rechargeable batteries anymore. I bought three combo Envelope (Sanyo), four batteries with charger sets and another package of twelve. I have one set on the charger at all times. I caught them on sale on Amazon. Been using them for years, they've paid for themselves many times over.
Generally speaking the rechargeable batteries with the larger milli-amp ratings last longer. But it isn't always price that tells the story, I have some off brand cheapies that work as well as the name brand. I've also tossed some as junk. Kind of a gamble that sometimes pays off. Like I said those with a higher milli-amp rating tend to last longer.