Hi J.,
My kids grew up watching the Simpsons, which I personally think is smart and hilarious in the way it satirizes all kinds of issues families deal with every day: school, politics, pets, aging, extended family, sibling rivalry, popular culture, corporate greed, divorce, bullying, homophobia...you name it. This was always our family's favorite show to watch together and I think it's because the humor works on so many levels...
My 15 year old son now loves both Family Guy and South Park (I know-yikes!) and my husband and I sometimes watch those shows, too.
My children are smart, funny, respectful and kind. They don't get into trouble at school, and they don't use bad language (at least not around us or any other adult that I'm aware of.)
It really comes down to your family's personal style and taste.
I think before you decide one way or another you need to watch the show with your son, at least that way he knows you're making an educated decision. TV ratings do not replace parental judgement :)