I think Jaws is Spielberg's best while The Godfather is not Coppola's best, but I still like Godfather more than Jaws.
It would be pretty difficult for me to pick just one film from Spielberg, but if I had to it wouldn't be Jaws. Jurassic Park would probably be the one, though Last Crusade has more meaning for me personally.
What do you think is Coppola's best?