Looking for a charger/battery backup for my new iPhone 4. Its gotta be light-weight, compact, and of course be able to charge the phone at a decent speed and with enough power to make it through the day. I'm flexible on pricing. If its worth the money, I'll buy it. Any suggestions would be appreciated, thx. I've seen ones made by Griffin, Kensington, Richard Solo. But i still have no idea which one would be the best.