The best, or most fitting, songs, songs that have, for some reason or other, stayed in your memory!
And I am talking about pop, rock, or other popular songs... songs which haven't been specially arranged or orchestrated for the JW-scored movie (so, for example, the Mandarin version of "Anything Goes" in ToD or "Suo Gan" from EotS don't count, since these versions were specially produced for their respective movies).
Examples that I like:
The opening of KotCS:
BotFOJ and Minority Report: