To solve that problem we are now using Stage file proxy. We have been using it for some time now to get files to stage or locally, and it works really well (we have some issues on D6-sites, but works almost flawless on D7-sites). Stage file proxy downloads the files that are requested from production (or whatever) site running environment.
So you just get the files you need, and you could easily delete the files locally and get them back when called for. Time and space saver.
A nice patch to the module is getting an admin-interface - so that you don’t need to add settings to settings.php or creating variables. EDIT: Greggles just committed that patch to dev :-)
Photo by James Butler