I don't know that this is necessarily an app but I would like some functionality when it comes to filing content. Right now, the Kindle only discerns between books and everything else. What I get is a page that everything from eBooks, audio books and subscriptions to anything I e-mail to it (PDFs). It would be nice to be able to file these things into different areas so I don't have it all jumbled together. There just aren't enough options in this regard.
