My tablet stores so many document files in various formats that I don't know myself what's there any more. I have stored there also files coming from other portable devices I've been using in the last years, so there's really a significant part of my life there, though in a way it's difficult to browse and search.
I think a great help to productivity would be an indexing system which presents document files stored in the tablets according to title, contents (possibly with some kind of dynamic tag cloud), document type and so on, like a library index. It should be able to read the several file types you can find on a tablet, including txt, html, odf, doc, xls, et cetera.
An indexing crawler daemon could be made to run only when the tablet is connected to the mains, to avoid draining the battery. Some kind of hash file could help to get instant results.
Also, a widget that lists the N last edited documents could be useful.
Discussion: http://talk.maemo.org/showthread.php?p=358153
