Ch, Ch, Ch, Ch, Changes.
Yes, maemo has had rsync for ages. Yes, rsync makes dumping stuff to the device really easy. Trouble is, when you are travelling around for a while, and when you have a little keyboard you tend to update some of those files.
Assuming the OOM (Only One Me) rule, Unison is a great tool to make the n810 much less of a data island and more of an extension of the desktop.
Check out my repository for the debs. You'll need to install gcc and binutils, complements of the way ocaml is currently built. So thats another 15mb of downloads or 40mb of card space you'll loose. The gcc thing should be able to be worked around to make a leaner install, but I wanted unison for use before the maemo summit. Kind of handy to sync stuff over and know you can edit it with the device. Of course you could always rsync from the device when you get home again, but unison is just a nicer bidirectional solution.