iOS Pick: Editorial
Leo Laporte's app cap on iOS Today 289 is Editorial by omz:software. This is a full word processor for the iPad, but it goes beyond the typical features that word processors offer. You can write in three different languages: Markdown, which allows you to do text formatting in plain text, TaskPaper, which is great for to-do lists and outlines, and Fountain, which takes natural language and converts it into the rigid format that screenplays require.
Editorial also has a ton of workflows and scripts that you can apply, such as sorting lists, inserting footnotes, creating PDFs, performing calculations, and more. You can even create your own workflows using Python. Editorial has support for Dropbox as well.