This is a great question for me because there's nothing I dread seeing more than this:
That's why portable mobile chargers make a lot of sense.
Here's a list of a few portable charger models that seem to have received very good reviews:
- New Trent iCarrier IMP120D
- Mophie Powerstation Duo
- Radio Shack Enercell 6000
I'd also recommend checking out Amazon and taking a good look at specs and prices. Ultimately, these products are similar to any electronic device - the closer a portable charging device matches your personal requirements, the more money I'm guessing it's worth spending.
Not sure I have the expertise to single out one product over the others here, but I have to say I like the sound of some of the solar portable chargers around.
I think solar power will be an area that mobile technology will become more and more familiar with, and users of mobile devices will demand it more and more from this point on.