I have a very scant collection of media files, but I do like this one for my mail notification:
http://miano.us/android/media/austin_mail.mp3
and....if/when I'm going to be in a more social setting for a couple of days:
http://miano.us/android/media/mail_mofo.mp3 (from the Euro Trip movie)
Enjoy 'em if you'd like 'em. : )