About a year and a half ago I was working on a screenplay and had an idea for a "word processor" of sorts. So I made it (Grandview, available in the Mac App Store for free). Since then I've made about 5 different apps, some for iPhone and some for Mac, all surrounding WRITING. My newest app is called Notesdeck.
Notesdeck is a simple notes app that syncs between the Mac, iPhone and iPad. It is everything I wanted to see in a notes app and even integrates with Simplenote, Evernote and Dropbox.