A5 - Takes notes in your browser. Elegant & simple.
Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.
Falcon for iOS - Writing notes made simple
Notational Velocity - Notational Velocity: modeless, mouseless Mac OS X note-taking application
Chars - Unicode Symbols Keyboard for iOS
Notational - Notes at the speed of thought