If you're looking for note-taking apps beyond just writing, the recently released Bamboo Paper app from Wacom is worth checking out. In addition to writing, the notebook-like interface also allows users to sketch and draw using a range of pen tools. The iOS, Android, Windows 8 and Kindle Fire OS compatible app is optimized for the Wacom Bamboo stylus, but any similar stylus will still work.
It's also possible to annotate images or photographs. Unlike other note-taking apps, Bamboo Paper allows you to turn your tablet into a full on notepad in a way that is as straight-forward as using a regular pen and paper. However, unlike a regular notebook, you can export and share what you create. There is even a zoom function so you can be as precise as possible.