One nice thing about so many rechargeable devices using USB is that I don't have to maintain a large selection of wall warts to keep things going. Each BOB has a small LiPo battery for recharging our phones, and my laptop bag has a larger one that I can use for my phone or my iPad. I backed Waka Waka Power on Kickstarter, so the small batteries in the BOBs will be replaced with those.

Other options for us include running a car, running the generator, or using one of the jumpstarters we keep in each car. One of those will run a smartphone or a Kindle for at least a week of heavy usage.