A must for creative types! Collaborative sketching on up to 4 iPads, voice chat and numerous awesome features make Sketchshare a worthy addition to any device. See others working in real-time, share easily and edit as required. All devs, designers and illustrators need this NOW!
Sketch n Draw is a drawing app for Android. It features 11 brushes, erasers, undo and redo functions, multiple canvas sizes and more. It could do with some upgrades but it's pretty decent!
Photo editing apps are ten-a-penny but I promise Paper Camera is worth trying out. Get effects like cartoon, sketch, comic book and noir applied directly to your camera. No more messing around after you've taken a photo; see how the shot will look with the effect before you snap it.
If you need to sign documents, take notes or doodle your way through a boring meeting, Penultimate is the app for you. Write and draw in bold gel ink, create and manage notebooks and produce excellent handwritten and drawn images without picking up a pen.