Godfather Part 2 (the Greatest film of all time in my opinion)
Once Upon a Time in America (Sergio Leone's crowning - and sprawling - masterpiece)
Angel Heart (Probably little more than a cameo for De Niro, but still quality)
Taxi Driver (Amongst the toughest 2 hrs in cinema history, but still worth it)
Raging Bull (Astounding performance and great picture)
The man is class.
Pisses all over Pacino - who, Godfather movies and Panic in Needle Park aside, is little more than America's answer to Brian Blessed.
Alright maybe Serpico then.