South Park is the funniest by far I think, I've even been there and it's a hole in the wall in my opinion. Next would be Beavis and Butthead, wish they were still around, one of the best shows MTV had. Last would be Family Guy, it's funny but all the random jokes get a little boring and expected.
Beavis and Butthead paved the way for cartoons like South Park where they talked about serious things and fixed them idiotically. Just like the real world. Beware of Government Control. Big Brother is watching You.