I think the earlier seasons were really funny in a relaxing and fresh way. I remember the episode called 'Petarded' , it was so funny. But I think as Seth started new projects he began ignoring family guy.
@ Jake - I agree American Dad! has good sense of humor and the characters are well adjusted but I do believe if there was no American Dad! then Family guy would have been much better because Seth would have to use all his jokes in Family guy and did not have to divide his material among his shows.