A great alternative to alkaline batteries is to use Eneloop rechargeable batteries for stored equipment. These are ultra-low discharge rechargeable batteries that keep 75% or more of their charge for 3 years of storage. Some of the newer ones are claiming 70% of charge after 10 years of storage! I have used these for a few years now and they definitely perform as advertised. These will not leak corrosive crap onto your electronic equipment, so it is safe to actually store them IN your electrical or electronic equipment, as long as said equipment doesn't draw power when off. Keep in mind, though, that some electronics will draw power even when off, so keep that in mind when storing as that might slowly drain your batteries.
I have tried a few other brands of low discharge rechargeables and none of them compares to the Eneloops in storage time longevity. As of now, I recommend ONLY getting Eneloops for any rechargeable battery applications.
http://www.panasonic.com/global/consumer/battery/eneloop/lineup.html
I use Eneloops in my handheld ham radio transceivers and I consider them to be the best thing since sliced bread as far as battery power goes. They have about 2000 milliamp-hours of storage, so they last a long time when the transceiver is being used as well as holding their charge when it is off. I have a shortwave receiver with them installed as well, but it has a clock so it draws power from the batteries over time. Even then, it's many months before I need to recharge them.
These are available online at Amazon and other outlets for roughly $3 or less per AA cell. Get some; they're worth every penny!