If we're going by awards, it's James Caan that shouldn't be in that group. They're all terrific actors, in my opinion.
Diane Keaton
1978 - Best Actress (Annie Hall) - Won
1982 - Best Actress (Reds) - Nominated
1997 - Best Actress (Marvin's Room) - Nominated
2004 - Best Actress (Something's Gotta Give) - Nominated
Al Pacino
1973 - Best Supporting Actor (The Godfather) - Nominated
1974 - Best Actor (Serpico) - Nominated
1975 - Best Actor (The Godfather: Part II) - Nominated
1976 - Best Actor (Dog Day Afternoon) - Nominated
1980 - Best Actor (...And Justice for All) - Nominated
1991 - Best Supporting Actor (Dick Tracy) - Nominated
1993 - Best Supporting Actor (Glengarry Glen Ross) - Nominated
1993 - Best Actor (Scent of a Woman) - Won
Robert De Niro
1975 - Best Supporting Actor (The Godfather: Part II) - Won
1977 - Best Actor (Taxi Driver) - Nominated
1979 - Best Actor (Deer Hunter) - Nominated
1981 - Best Actor (Raging Bull) - Won
1991 - Best Actor (Awakenings) - Nominated
1992 - Best Actor (Cape Fear) - Nominated
Marlon Brando
1952 - Best Actor (A Streetcar Named Desire) - Nominated
1953 - Best Actor (Viva Zapata!) - Nominated
1954 - Best Actor (Julius Caesar) - Nominated
1955 - Best Actor (On the Waterfront) - Won
1958 - Best Actor (Sayonara) - Nominated
1973 - Best Actor (The Godfather) - Won
1974 - Best Actor (Ultimo tango a Parigi) - Nominated
1990 - Best Supporting Actor (A Dry White Season) - Nominated
Robert Duvall
1973 - Best Supporting Actor (The Godfather) - Nominated
1980 - Best Supporting Actor (Apocalypse Now) - Nominated
1981 - Best Actor (The Great Santini) - Nominated
1984 - Best Actor (Tender Mercies) - Won
1998 - Best Actor (The Apostle) - Nominated
1999 - Best Supporting Actor (A Civil Action) - Nominated
James Caan
1973 - Best Supporting Actor (The Godfather) - Nominated