Panasonic Eneloops and similar modern low-self-discharge NiMH batteries are really nice. Their capacity is not quite as high as alkalines, but their internal resistance is an order of magnitude lower. At loads over 100mA, they're a far superior battery in both ability to deliver power and effective capacity. They have low self-discharge, so you can charge them after using them instead of discovering you need to charge them before using them. And I've never had one leak, but I assume they can.