If you ever feel like changing your login sound it’s a piece of cake. Go to Preferences -> Startup Applications. Look for an application called “GNOME Login Sound” and click edit. Delete the previous command and use vlc running in daemon mode (-d) to play the file of your choosing.
vlc /path/to/file.ext -d
This will work will almost any type of sound file (ogg, mp3, wav, et cetera.)