Yes, I realized it's odd to be obsessed with a reusable battery, but these are great and can't help but telling people. Friends in Seattle & Portland: consider this a public service announcement to better your life.
I just discovered Bettery a few weeks ago in a Redbox-like vending machine at my local Whole Foods. As photographers, we go through TONS of AA batteries for our flashes, and I'd yet to find a reusable one that packed enough kick. These last longer than regular batteries in our flashes AND I no longer have to feel like a guilty mother nature killer each time I drop batteries in the trash.
Basically, you get them from the machine, use them and return them when they are dead. No remembering to charge things, yay!
Seriously, I could go on and on, but for all my photographer friends out there, and anyone else who uses a lot of batteries, you should give these a whirl. They're about the same cost as disposable ones.
PS. I feel like I should mention that I really am just a huge fan of these, this is totally my own opinion and I wasn't compensated in any way for this post. I just really like these batteries. A lot.