I know this article is about graphics, but you left out polka's strong influence south of you. The spanish 'Tejano' music, which is very popular latin music, is a great mix of spanish music styles with the German accordion polka. The late Texas latin pop singer Selena (www.selena.org) sang mostly Tejano before her pop stardom. The most popular radio station in Texas is Tejano. So polka alone may be quite boring, but when you mix it with other flavors (graphically too), you get a great result.