nvUltra is an upcoming note-taking app from Brett Terpstra and Fletcher Penney. It's currently in private beta, but you can sign up below for updates as development finishes up.
Put all your thoughts in one place. Just start typing to create a new note.
Any folder on your Mac can be a notebook, and you can start a new one any time. Switch between them and have multiple notebooks open at once.
nvUltra comes with multiple editor themes, and you can create your own.