Louis Armstrong is the only artist in our 300 Songs countdown to get 10 songs to himself (five songs below and the other five online)—the least we can do for the most towering artist in the city’s music history. Looking over the list of songs that writer John Swenson has chosen you’ll find a trenchant piece of social commentary, one of the warmest evocations of the South on record, a pair of beloved pop songs, an...