We're not trying to exclude those who use smartphones not of the Apple variety—it's just that the iPhone clearly needs the battery bump the most. While there are myriad new choices of external iPhone battery packs—the Mili PowerSpring 4 comes to mind—none outshines the Mophie Juice Pack Air, which weights a mere 2.5 ounces and incorporates one of the more well-designed cases available. Mophie claims the 1500 mAh minimum-capacity battery will double your iPhone's battery life (reality: not exactly, but close enough) and it elegantly communicates with the user via a four-bar white LED string to show available charge and a red/green standby/charging switch. Plus, when used as a charger for totally depleted handhelds, the Mophie can punch an iPhone's available juice back up to 70 percent or so. 

COST: $79.95 at mophie.com.