Mean Streets has the best soundtrack of all of Scorsese's movies.
Raging Bull has the best score, followed by Taxi Driver's jazz. Donnie Brasco's "Donnie and Lefty" score is also beautiful. Once Upon a Time in America's score is powerful as well as Road to Perdition. Pulp Fiction has an excellent soundtrack. Casino is also very great.
The Godfather has a classic score.