Something. Runners-up: Blackbird. Penny Lane. Strawberry Fields Forever. Don't Let Me Down. Here, There And Everywhere.
The arrangement might be straight-forward, but it's not the simplest song! It's in G major, I believe. In the verse, he goes: G (the root -- ok, standard) F#7 (7th -- a little unusual) Bm (the 3 chord) C (4 chord) D (5 chord) G (root) F#7 (7th) C (4 chord) D (5 chord) G (root) F#7 (7th) F (7th, but it's actually not in the key, so he's modulating off of G major) D (5 chord) G (root) So the verse has this unusual chord progression that even includes a brief modulation off of the key.
nice description, I agree. my longtime favorite as well. other tracks have threatened its position (Cry Baby Cry etc), but I've never called another song my favorite of theirs.
Tie: "If I Fell" and "The Things We Said Today" I can't even put just one of these on repeat. They're on a playlist together!