New Trent Easypak 7000mAh Portable Triple USB Port External Battery Charger/Power Pack for Smartphones, Tablets and more (w/built-in USB cable)
My Android Samsung Charge is notorious for having a short battery life, fully charging the Easypak gives me two full charges (and that's after I had the Easypak sitting in my bag for over a week).  The only thing that I found a little irritating was that if you leave it charging and the phone drains the Easypak, the Easypak goes completely dead.  The first time I used it fully, I thought the Easypak had broken.  Other than that, it's absolutely worth the $30 if you think about all the batteries you don't ne