4) 'I Will'
From 'The Beatles' (1968)
There's so much going on in 'I Will' that, it's hard to believe that, at 1:45, it's one of the shortest songs in the Beatles' entire catalog. The lyric isn't quite cohesive -- one moment Paul is unsure of her name, the next he's declaring his eternal love -- but it doesn't really matter too much. Between the beautiful melody, the acoustic guitar riff between the verses, and its immediacy, this has been a favorite since its release on 'The Beatles' in 1968. And the way McCartney effortlessly introduces new musical ideas into the coda is the mark of a songwriter at the very top of his game.
Listen to 'I Will' by the Beatles