A few months ago dropbox was a Debian packge in non-free. Recently I noticed that there are several new versions available and tried to notifiy the maintainer and ask him to update the package. But unfortunately it looks like the package is not available any more (Here's why).
However getting Dropbox is quite easy if you know what to do.
The obvious choice would be to go to dropbox.com and download either the source package and compile it yourself or try to install the precompiled Ubuntu packages. The first option is not really an option for most users and the second one does currently not work on Debian/Sid (aka unstable).
However, there is an easy solution: on the download page search for the
CLI script (currently it is named dropbox.py) Download that and run it
python dropbox.py start -i. That will download the propritary
~/.dropbox-dist. Now go into that folder and start
dropboxd. There you go, you have a fully working systray app for
Depending on your desktop environment you might want to put
in your "autostart". So you don't have to start the daemon every time
you login. And that's it.
It is not really ideal, since a Debian package would be much better for updates, security, yada yada, but it's still better than nothing.