Music Thread: Songs to hear at least once before you die

[jeffnc]

OP was asking about "songs", but since classical music has been brought up....

Beethoven's piano sonatas, such as Pathetique and Moonlight. Beautiful. The former provided the tune for Billy Joel's "This Night" from Innocent Man, among others. The Beatles played a chord progression from the latter in reverse on "Because" from the Abbey Road album, among others.