"Ooh La La" by Faces in Rushmore

A beautiful film with a beautiful ending featuring a beautiful song. Every character shuffles into the frame as if at the end of a play before curtains.

Of course the song's lyrics couldn't be more appropriate for this film and specifically this moment in the film. Boyhood, aging, relationship with inner child and earned wisdom.

A couple of other contenders were "Making Time" to the yearbook montage and this incredible version of the The Who's "A Quick One While He's Away"