I've been really liking an iPad sketching app called Paper. It's not a full-fledged Art Application; for example, it doesn't do layers. It has a minimalist but nice interface, with few settings; the emphasis is on simplicity. It's especially good for stuff like quick concept drawings, sketching workflows, getting visual ideas down.
But some people are also using it to create really nice art. The app recently added a feature called Made with Paper that showcases stuff created by their users, and I love some of the art they're showing there. Thought I'd link to some examples:
- Architect Michael Leckman's Night scene study.
- Interaction designer and illustrator Zhen's Unzip a World of Colors. (And a bunch of other pieces from Zhen on Paper.)
- A sketch/portrait by Ronald Cuyán.
- A stormy seascape by Veryman.
- Most of Sylvia Lynch's work, but especially St. Cuthbert and the Otters.