The best Beach Boys song ever? That's easy, I said as much here. Tho' a much better category, I think, would be best non-Beach Boys Beach Boys song. Jan and Dean's You Really Know How to Hurt a Guy anyone? Or maybe Beach Baby Beach by First Class? Strong contenders both.
However, for my money, there's only one homage that really gets inside the head of Brian Wilson; in fact, someone far more astute than me once said about this record that it's like Neil Sedaka up on stage with the Beach Boys; you won't find me arguing with that.
Possibly Roy Wood's finest moment...
Roy Wood - Forever (1974)