Education Google Earth (Free) - Google Earth is one of my favorite computer programs, and it's especially great on the iPad. View high-resolution satellite photos from all over the world. Navigate terrain with a swipe of the finger and bring up fascinating information with a tap.
Star Walk ($5) - What's better than a warm summer evening gazing up into an endless field of stars? Doing it with Star Walk! This app tells you what stars and constellations you're looking at using augmented reality. It has tons of interesting facts, and can help you find specific stars and planets.
Creativity Snapseed ($5) - The iPad is great for taking photos. With Snapseed, it's also great for editing them. Snapseed is an easy-to-use photo editor with dozens of customizable options to tweak, filter, correct and alter your pictures. You can even share them online right from the app.
SketchBook Pro ($2) - SketchBook Pro is an exceptional drawing program for the iPad. It gives you a bevy of features. You can adjust brush color and size. And you get a slew of brush styles. You can edit multiple layers. There are several blending modes. The list goes on and on. It's a must for creative types.