first off if some esle already found this, please don't kill me.: p
so to have a media file on your zune but not on your computer,you have to.....very simply........ just........ delete the file from your comp, but not from your zune marketplace.:shocked: the file will still appear in your library, but as long as you don't use the file it'll be fine.
so yeah, i found this on accident so...... yeah