If you need a free iPad note-taking app that syncs with Dropbox or Box.net, PaperPort Notes is a great option, especially for its speech-to-text dictation tool. It contains a few slightly off interface design choices, but is an all-around great option for a free app.
This looks very interesting. When I first saw it I thought it might be useful for taking notes at a seminar. However I am now thinking it might be useful in the dental office to make patient treatment notes. It is free, might be worth a try.