The Best Portable Rechargeable Battery Gadget

I’ve been messing around with AA rechargeable batteries for a while now, and I just discovered what might be the ultimate related gadget: a USB power pack that can charge both ways. This is a multifunction device that has the form factor, and same primary function as those iPod/Cellphone emergency chargers, except these can also recharge the four rechargeable AAAs you put inside. These are already available, and cost about $30. Seems like the perfect mobile accessory to me.. (Charge all my portable devices, plus, if I have a device that needs AAs, I can take these out).
I just ordered this one from Amazon:, and I’ll update this post with a review after I get a chance to test it out. I’m looking forward to being able to charge my cellphones on the go, plus my iPod, plus my video camera, plus my everything else!