Actually, I think he is a more respectable composer, properly, than he is given credit for. He is considered in a more serious light by many in Europe-- he has a couple of albums with the London Symphony and some modern orchestras in Germany, et al, have performed his work. He is at least good enough to be taken seriously over there.
Hey, I know this is mostly tongue-in-cheek. But seriously - how do you know Zappa is the World’s Greatest Composer? How familiar are you with Sibelius’ 4th Symphony? I think Sibelius is the World’s Greatest Composer. (They named the reportedly the world’s best music-notation software after him. See? See? http://www.sibelius.com ) So he is the World’s Greatest Composer…because I said so! 
You can have the thread back now…