Good work. I really like the idea.
1. I agree regarding the aforementioned opinion on the titling of notes. If no personal title is entered, the note should display the first line of the note in the overview list.
2. When you create a new note, the title is highlited and can be entered. However, as soon as the orientation of the phone changes (e.g. to landscape) the cursor is in the beginning of the text field and the title of the note cannot be changed. The same goes for the use of a hardware keyboard. When I flip my Desire Z open to use the hardware keyboard the same thing happens.
3. Deleting notes: The app should refresh by taking the latest changes into account. If I remove the note on the phone it should disappear from Dropbox. If I delete a file from dropbox, it should delete the note in the app.
4. Discarding notes. It should be possible to get back to the list view without saving a note. It's a good idea to have the note saved automatically when you press back. But you might provide a "discard note" option when you press "menu" while editing a note.