Snapseed by Nik Software (Acquired by Google)
Snapseed is another award winning photo application for the iPad and Mac desktop. Snapseed's high ranking above other apps is largely attributed to its UI and the way it takes advantage of multi-touch gestures that are unique to the touchscreen interface. Without using the physical presence of tools, Snapseed relies on press, slide, and pull gestures on the iPad surface to enact menu options and to apply filters and effects. The result is a unique iPad experience for augmenting photos that is unlike anything you will experience on apps that offer similar features. Snapseed is $4.99 in the App Store.