Not a song (yet), but this piece by Joyce Grenfell struck me as the perfect epitaph when I read it many years ago; I came across it again recently. "If i should die before the rest of you, Break not a flower nor inscribe a stone, Nor when I'm gone speak in a Sunday voice, But be the usual selves that I have known. Weep, if you must. Parting is hell, But life goes on, So sing as well.