Elizabeth, thanks for reminding me about " Die Kluge ". You are so right. Must dig it out and listen again. For me:
Schubert, Quintet in C, 2nd movement and the beginning bars of Mozart's Requiem. In another vein: Bach's Magnificat and the main theme of his "Musical Offering", Mahler: Kindertotenlieder with Kathleen Ferrier....and "Ella Fitzgerald sings the Blues".