Mr. dB said:
I could make a good case for any of the songs in this thread.
The opening scene in "The Beatles Anthology" video where they're showing the docks of Liverpool while the soundtrack plays "In My Life" is one of the most perfect moments in TV history.
I tend to come down on the Lennon side of the Lennon-McCartney debate, but Lennon and McCartney both got trumped by the third songwriter in that band, "Something" by George Harrison is their most beautiful love song.