The iPhone 4's battery is already rock-solid, but even it has a tough time against Rage HD or 3G Netflix streaming. So when Mophie says they've got a pack that can double the iPhone 4's battery life, I listen.
The Mophie Juice Pack Plus weighs in at 2,000 mAh, making it the most potent of an iPhone 4 case yet. Your iPhone might look like it let its diet slip, but it's a minor sacrifice with a major benefit. What might hurt more is your wallet—the Juice Pack Plus costs $100, twenty bucks more than Mophie's smaller-capacity Juice Pack Air model. [Mophie]