Had to make this thread because i really enjoy this and i was talking about it with a few friends awhile ago.
I really enjoy both of these tv programes but if i had to choose i would have to say Family Guy due to the fact that there are alot more funny stuff happening in it.
I'd say American Dad, because I'd say that that show is more "Actiony" because of Stan being a C.I.A agent. All of these adventures he goes to, killing, and messing with his neighbors. Like one episode, his neighbors pissed him off, and now he made all of them leave their house to protect against the terrorists or something. (No racism intended)
American Dad, the episodes actually have a small plot with slips of comedy inside them. Opposed to Family Guy which is just crude humor of people getting hurt and making racist, sexist or biased jokes.