My favourite scene from Cape Fear (spoilers)
Source: http://www.youtube.com/watch?v=Z7xJxo223YA
He did go over the top, but Max Caddie is just that kind of character. Scorsese really embraced the slasher horror element to the final confrontation too, so it all just works at that point to go that big with the performance. He becomes a larger than life presence in that final act.
A lot of people say DeNiro goes over the top but whatever.