The mile has a place of honor in rock and pop song lyrics. Whether you are "Eight Miles High" (Byrds) or "A Million Miles Away" (Plimsouls), or just a measly "500 Miles" (Proclaimers) from the promised land, songs that mention the mile will get you there in style.
The kilometer is not so lucky. Where are the classic tunes about kilometers? It simply doesn't work as a narrative element: "I just can't take the pain/Of the kilometers between us, babe" -- no thanks. Of course, part of the explanation may be that pop music in the last half-century has been dominated by Anglo-American culture, and the mile makes sense to us. But I think it goes deeper than that. "Kilometer" (or "kilometre," if you prefer) is not easy to sing -- too many syllables. And it has a rather cold, technical quality. Its composite, inorganic nature -- 1000 individual meters, and no scrimping, please -- is too obvious for it to fit well in the world of sex, drugs and rock 'n roll. The kilometer is just unsexy.