They are all three good.
I voted for Family Guy, but I also like the other two.
The only problem I can see with Simpsons is that it has been around far too long and seems to have lost its touch. I loved the older episodes, I cant say that for the newer ones. They are decent enough to pass, but nothing like the old ones.
Scrubs always makes me laugh. That darn black doctor cracks me up!
Family Guy however has to take the gold. There has not been a time that I have watched it and not laughed atleast once. Any show that has Stewie and Peter is awesome in my eyes.