Never got on with Family Guy's humour. It's exceptionally formulaic, and the irreverent cuts and 'whacky' stuff simply isn't funny, to me. The Simpsons has also gone down the pan, I've not really watched a new episode from the past 5 years or so, but they were getting bad even then. During it's height though, it was glorious. Had about 10 seasons maybe where it was brilliant. Therefore Homer wins it by miles for me.
Funniest cartoon dad as of right now is easily Stan Marsh. Funniest character in South Park, pretty much any episode featuring him as a main character is brilliant.
'It's ectoplasm!'