Now that's what I call convenient! I use rechargeable batteries every single day in my digital camera and other devices. I could not do with buying batteries every single day or so, and the rechargeables have been wonderful.
Now, they have come out with a USBCell that recharges the 'batteries' via the USB on any computer. Just plug the battery/cell in and charge it up, rendering it useful when on the go, on vacation or just plain "busy".
More compact than carrying around a battery charger with extra batteries, the USBCell will give you more room in your cases. Cameras, MP3 players, portable devices, anything that needs juice can use the USBCells.
Moxia Energy has certainly come up with a great idea here. Simple, reusable energy is the tagline for the site. I'm definitely purchasing a pair or two for my home. Sold for £12.99 I think they are well-priced for most any user.
Only available in the UK right now, they do offer a mailout notification when they become available in the US. It makes me want to find my favorite UK friend and see how we can work out some shipping!