The ability to backup the metadata from my media library would give me a lot of peace of mind. In the catastrophic event of a hard drive failure, ripping/downloading the albums would take time, but the most difficult thing to restore would be the tags.
As far as I know there's nothing which can do this at the moment, although I know it has been asked about before. foo_jesus (http://www.hydrogenaudio.org/forums/index.php?showtopic=68528) backs up the database, which i think has all the information in it, but there's no way to import it again. foo_customdb (http://www.hydrogenaudio.org/forums/index.php?showtopic=75306) is more for complementing your tags than backing it up, and again there's no import functionality.
A component which could backup your metadata into a file in a dropbox monitored folder, and which lets you tag albums using that database while ripping or from the context menu would be great. Given foobar's emphasis on properly tagged files and the community's obsession with tag standards, I'm a little surprised that there isn't already some way do do this.