I wouldn't be willing to pay enough attention to the mechnanized tantrums that come out of the loudspeakers these days to *rank* them; but of the songs that are actually sung & enjoyed by people I know & like, I think "Harriet Tubman" by Walter Robinson takes the prize. It contains no information about its subject; instead we get unimaginable imagery (a train with a lifeline & a first mate) and unparsable syntax. I am ordinarily latitudinarian at sings, but when that one started I conceived an errand in the kitchen.

Of the songs mentioned by others in this thread, I am happy to say that I have heard very few. Of those, I rather admire "Kilkelly, Ireland" (interesting people), "Onward, Christian Soldiers" (tho an atheist, I am a sucker for hymns), and "Puff, the Magic Dragon". As to the last, the consensus on rec.music.folk used to be that the druggy allusions were not intentional. In any case, it contains a sentiment far more subversive than cocaine, in the line

A dragon lives forever, but not so little boys,

which equates growing up with death -- quite correctly, of course, in the long run.