Is it the melody of 'All The Things You Are' that pleases the ear or the chord sequence?
It's the chord sequence that pleases me. Chop the melody statements off and the magic's still there.
Even outside jazz I suspect a lot of what we think of as great melodies have their impact because of the harmonies. I've been a sucker for a good or unexpected chord change since I first started listening consciously to music (and probably before then).
Example - at the end of the 1st movement of Vaughan Williams 6th Symphony this glowing, soaring melody appears that turns you to mush. Yet it's been thrown around the orchestra for the whole of the movement without anything like that effect - it's the way it's harmonised at the end that sees it suddenly emerge as a gorgeous melody.
I use the word "changes" in the jazz sense to mean chord sequence.
I've listened to so much jazz that I think in terms of beautiful changes, rather than melodies, so I'm nominating "Cherokee", "All the Things You Are" and "Body and Soul".