1930s - Henry Armstrong 1940s - Joe Louis 1950s - Ray Robinson 1960s - Ali 1970s - Duran 1980s - Ray Leonard 1990s - Pernell Whitaker 2000s - Manny Pacquiao
1960's: Ali 1970's: Duran 1980's: Tyson 1990's: Whittaker 2000's: Mayweather Won't even pretend to have an opinion on any era before this.
Perhaps.... 1880-1889: Charlie Mitchell 1890-1899: Bob Fitzsimmons 1900-1909: Joe Gans 1910-1919: Sam Langford 1920-1929: Harry Greb 1930-1939: Henry Armstrong 1940-1949: Ray Robinson 1950-1959: Ray Robinson 1960-1969: Muhammad Ali 1970-1979: Roberto Duran 1980-1989: Ray Leonard 1990-1999: Pernell Whitaker 2000-2009: Manny Pacquiao