South Park vs Simpsons vs Family Guy POLL Watch
In that order. The cartoon wars double episode of SP sums up why SP is superior to FG for me.
Then Family Guy.
Then South Park.
The Simpsons, as a whole, would probably be ranked the highest I'd say - they've mastered every quality a comedy tv show needs. I prefer south park to it now, but over its lifespan simpsons comes out on top.