For $45, the Proporta USB Mobile Device Charger looks well worth the purchase price if Arne’s review is any indication. The unit houses a 3400 mAh rechargeable battery that can be juiced up through the USB port of a laptop or desktop. When you’re not charging the internal battery, you can use the stored power to extend the battery run-time of mobile phones from Sony Ericsson or Nokia, plus if you’ve got a device that charges via a mini-USB cable, you can power that too. Just about every HTC phone I can think of uses this method, so that option is particularly appealing to me. Tipping the scales at just 120 grams and measuring just 100 x 62 x 15 mm, this is light enough to carry around all day.