Peter would wreck Homer.

The original American family guy takes it.

Homer can't be knocked out and gets shot with cannon balls but he did get beat up by George Bush. He did beat up Mr. Burns, not much of a feat.

Peter has had at least three epic battles with the giant chicken. He's got some good durability. Peters lame feat is knocking out a woman who looks like a man.

I really don't see either winning, and depending on the location, in the end they both end up bloody and bruised in either Moe's or the Bearded Clam.

Homer wins and Maggie beats Stewie