If you are talking about what show will finish first, it's The Simpsons. Reason being: The Simpsons have been around for how long? I think 12 or so years. South Park isn't that old. The Simpsons have done just about as much as they can, South Park is still on it's first wind.

I like The Simpsons a hell of a lot more than South Park; I don't get their humor some times. It's just the fact that The Simpsons have been around for a longer time, so they will die out sooner. Sad, but true.