Budd Boetticher's The Rise and Fall of Legs Diamond (1960)

The Rise and Fall of Legs Diamond is a minor classic in the perverse Scarface tradition.
--Andrew Sarris

The gangster is the man of the city, with the city's language and knowledge, with its queer and its terrible daring, carrying his life in his hand like a placard, like a club.
--Robert Warshaw, The Gangster as Tragic Hero.

There is no doubt in my mind that the demise of the gangster film, in spite of many attempts to keep it alive, has to do with almost all films being made now in color and the shifting of locales to rural areas, e.g., Bonnie and Clyde (1967), as well as the changes in the production code that allow gangsters to sometimes escape death. Boetticher's film is one of the last classic gangster films, though it had to be a period piece, since Prohibition is so important to the gangster.  But gangsters have since shifted now to the corporate world (Samuel Fuller's Underworld U.S.A., 1961) or the Mafia family (The Godfather, 1972), leaving little power to the individual.

The Rise and Fall of Legs Diamond was made after Boetticher's series of austere and beautiful Westerns (which thrive on color), with Ray Danton playing Diamond the dancer who became a gang leader and was finally felled by his own narcissism and his inability to care about anybody but himself.  As is often the case with gangster films one is drawn into the clever and ruthless rise to power, until that power becomes an end in itself and leads to destruction. The black-and-white was handled by cinematographer Lucian Ballard, who previously worked on Boetticher's The Killer is Loose (1956) and later on color films for Sam Peckinpah.  Boetticher and Ballard are among those filmmakers from the classical era who knew the work of D.W. Griffith (who made the first gangster film, The Musketeers of Pig Alley,1912) and Josef Von Sternberg, who made Underworld in 1927.  They also pay tribute to the first gangster films in sound, which allowed one to hear the noises of motorcars and machine guns:  Mervyn Leroy's Little Caesar (1930), William Wellman's Public Enemy (1931) and Howard Hawks's Scarface (1932).

Sergio Leone's Once Upon a Time in America (1984) did not revive the gangster film the way his Westerns revived the Western, at least for a time.  But Leone's film was also a period piece; whereas the Western is almost infinitely malleable in time and space the classic gangster film (as opposed to the heist film, the thriller or other variations) is extremely limited in its time period and its iconography.