I've pretty much decided that I'm going to use Energizer Ultimate Lithium AA Batteries in my NIkon MD4 drives. The main thing is the fact that they can't leak. This is important to me because I use my MD4s in spurts. I may use them several times a week for short periods, followed by no use for months at a time. Any comments? Especially from photo.net members who use the lithium batteries... Thanks.