iExpander is a kickstarter project for iPhone that really got my attention. It basically let's you have a better camera for low-light images, an expandable SD memory slot, and double the battery life. It is compatible with the new iPhone 5 as well as previous iPhones. The iPhone 5 version even converts the lightning port to a 30-pin connector port on your iPhone 5, so if you're worried about the number of $29 adapters that you need to buy, this case will solve your problem.
To double the battery life, the iExpander team put in another battery just like the one that comes with your iPhone 5. Now you have two batteries in your iPhone, because having one battery is too mainstream.
The team promise a big improvement in low-light images. They have adjusted the LED flash to add more light energy and increase the distance of the flash of the iPhone leading to 'unbelievable' results. The before and after images below should prove the point. For some reason I still feel a bit uncertain about the reliability of these images.