More than just a simple note-taking app, the Pad & Quill app ($1) acts as your virtual library by organizing your notes in separate sections, or in this case, separate "books." Have one book for work notes, another for private, school, activities, food journal, etc, and the Pad & Quill app will keep you organized (instead of tossing all your notes into one stack like the native Notes app does).
You can customize your virtual book covers, fonts, paper style, and more, as well as sync your notes across your iDevices. You can even email yourself the notes if you need to share. Plus, it just looks way nicer than your standard note app. Who can argue with that?