I'm continuing to appreciate the Kensington line of portable batteries and chargers for iPods and other portable devices (see earlier post).
For example, the Kensington Rechargeable Pocket Booster is a clever option for having an auxiliary power boost on the go. It's a portable battery with a USB outlet, so it works with lots of handheld devices. (It comes with a mini-USB cable and micro-USB adapter, or you can use the cable that comes with your device, i.e., the Apple iPod cable).
Plus -- the Pocket Booster is powered by two rechargeable NiMH AAA batteries, so you can not only recharge it easily (there's a USB connector under the end cap), but you also can swap in additional batteries if needed to keep on charging. And, as a bonus, you even can pull out the batteries in a pinch to use them for other portable devices, such as a Bluetooth mouse.
The Kensington Pocket Booster is small and light (2/3 ounces), and priced at $34 (around $19 street).
Then for charging up your collection of devices, the Kensington 4-Port USB Charger for Mobile Devices has outlets to spare, with four USB power ports, so you can charge up to four mobile devices simultaneously. You can use your existing USB charging cables, or check out the Kensington line of USB Power Tips for various devices.
The Kensington 4-Port USB Charger is priced at $29 (around $19 street).
See my Portable Power Accessories Gallery for more on portable chargers
Find the Kensington Pocket Booster
and 4-Port USB Charger on Amazon.com