The Girl From Ipanema

Everyone knows the first section. It's the second one that separates the players who did the work from the ones who didn't: the tune leaves F and passes through ten tonal centres before coming home, all in a handful of bars.

Forty-six chords, half of them dominants. The dominant is the chord that allows the most choice — which is why it's where a solo most clearly shows a player's level. Hitting a right note here is easy; making the right choice is what shows.