Extra Heavy Duty Duracell Batteries (half black, half goldy colour) are the bees knees.
We use them in the Alarm Industry and they last for 5 years and I have never had a leaky battery ever, even after 5 years in many, many hunreds, if not thousands of alarm detectors. I use them in my pinball machines. Cheap batteries leak, sometimes after just 4 or 5 months. It pays to spend up front.