Scorsese did a great job of mixing '50s rock and roll ballads with 60's rock. Noticeably missing from most of Scorsese's movies is the classical pop music that is most often connected to mobsters, i.e., Sinatra, The Rat Pack, etc. I'm not sure if it's a personal aversion (he's clearly a rock and roller, he even worked on the Woodstock movie), or if it's just to better represent the viewpoint of the lead characters, be it Charlie in Mean Streets or Henry Hill in Goodfellas, who are both about the same age. These guys didn't grow up on swing jazz. They grew up on The Beatles and Motown. In Casino, Scorsese used a lot more of the Rat Pack, classical pop music, as Ace Roethstein was about a decade older than most of the other Scorsese leads. Of course, Robbie Robertson of The Band was music director for many of Scorsese's 80's and 90's movies, so a lot of these decisions could have had to do with his personal taste.