As a photography nut, I'd never give up my camera for the one on my phone, but that doesn't mean that I don't constantly snap candids with my iPhone. Of course, it could be a better camera, but I wouldn't have dreamed it was so easy to improve it and protect it at the same time!
Griffin's Clarifi Case ($35) does much more than keep your phone safe from scratches; its built-in close-up lens covers the iPhone's lens, while enhancing the details and colors in your pictures.
Check out Griffin's side-by-side examples of photos taken with just the iPhone, and then one taken with the case. Pretty big difference, I'd say.
It's great for apps that read your pictures, scanning documents to email, and even just for taking the odd photo — who doesn't want a better camera phone?