If you like to take photos on your iOS device, grab Snapseed. If you already have it, you'll see an update today that really adds some nice features.
This latest release adds two very important features. One is called HDR scape, which gives your images an HDR look that can be as natural or as unnatural as you like. You also get a shadows slider that lets you increase shadow detail without ruining the overall look of the image.
The app also offers auto enhancement, a selection of frames, black and white presets and tilt-shift effects.
I found the new features impressive. If I didn't go over the top on the HDR settings, I could get a very much improved landscape image. The shadows slider also worked well, and kept the image looking natural rather than over-processed.
Snapseed has been great since it was first released as a paid app. Happily, it's been kept up to date, and for many photographers it will be the only photo enhancer/editor they will ever need.
Snapseed is a universal app and requires iOS 7 at the moment. There is a warning about using this latest version on iOS 5 or 6, and there will be a fix and an update soon. The issues involve sharing images to those older devices.