There are camera apps for the iPhone that claim to do it all, and some come very close. Newcomer Zitrr Camera (US$0.99, on sale through Tuesday) claims to be the only camera app you'll ever need. With a couple of caveats, it qualifies for the title.
The app has a variety of useful shooting modes, including HD video, a timer mode, a burst mode (rapidly shoot frames one after the other), anti-shake software, a big button for larger controls to make shooting easier and even a barcode scanner.
Zitrr Camera features 34 live effects, so rather than add them after the image is taken, you can actually set up the filter and see it applied live on your screen. This is very helpful. You can tap the screen to focus and adjust the white balance controls. The app provides a histogram, sharing with all your favorite social networks, and filters that can be applied after the fact. Zitrr Camera also creates slide shows, on-screen guides for composition and a level.
That's a lot, but not everything. Zitrr camera also gives you digitally created lenses like fisheye and tilt-shift. It has a collection of frames, and photos can be titled.
As you can see, there are a boatload of features in this one app. I used it to take some artsy (to me) photos of my parrot, which I have placed in the gallery.