New Trent Easypak 7000mAh Portable Triple USB Port External Battery Charger/Power Pack for Smartphones, Tablets and more (w/built-in USB cable)
Bought this for my wife, nice that it has incorporated charging cables.  Although, if the charging cable for the unit breaks, there is no other way to charge it (that cable is pretty short too, it hangs from the wall if there is no table close).<br />Works perfectly and charges our Android phones and tablets (Tablet charging drains it fast though).