Would like to offer typical URLs - e.g. http://wagn.org/themesong.mp3 that work as expected - rather than taking people to a card from which they have to click again. This also supports maintain canonical URLs from migrating sites.
The way that file formats are evolving, I imagine something like this:
Same for .m4a, .mov, etc. See http://www.fileinfo.com/filetypes/audio and http://www.fileinfo.com/filetypes/video
+discussed in support tickets
+relevant user stories