As of 1990...
Leader of the People's Republic of China:
1949-1953: Mao Tse-tung (CPC)
1953-1956: Zhu De (CPC)
1956-1958: Deng Xiaoping (CPC)
1958-1959: Lin Biao (Junta/Military)
1959-1965: Jiang Qing (CPC)
1965-1972: Aisin-Gioro Puyi (CPC)
1972-1985: Deng Xiaoping (PPC)
1985-1990: Constitutional Convention
General Secretary of the Soviet Union:
1922 - 1949: Joseph Stalin (CPSU)
1949 - 1974: Georgy Zhukov (CPSU)
1974 - 1980: Alexei Kosygin (CPSU)
1980 - present: Nikolai Ryzhkov (CPSU)
President of the Republic of France:
1947 - 1954: Vincent Auriol (SFIO)
1954 - 1958: Georges Bidault (Popular Republican)
1958 - 1966: Charles de Gaulle (UNR)
1966 - 1975: Francois Mitterand (FGDS)
1975 - 1988: Lionel Jospin (FGDS)
1988 - present: Jacques Chirac (RPR)
Prime Minister of the United Kingdom:
1947 - 1951: Clement Attlee (Labour)
1951 - 1955: Winston Churchill (Conservative)
1955 - 1956: Anthony Eden (Conservative)
1956 - 1959: Harold MacMillan (Conservative)
1959 - 1966: Hugh Gaitskell (Labour)
1966 - 1970: Edward Heath (Conservative)
1970 - 1979: Harold Wilson (Labour)
1979 - 1987: Geoffrey Howe (Conservative)
1987 - present: Roy Hattersley (Labour)
President of the United States:
1945-1953: Harry S. Truman (Democratic)
1953 - 1961: Estes Kefauver (Democratic)
1961 - 1969: Nelson Rockefeller (Republican)
1969 - 1973: Harold Stassen (Republican)
1973 - 1975: Henry M. Jackson (Democratic)
1975 - 1985: Terry Sanford (Democratic)
1985 - present: Alexander Haig (Republican)
Chancellor of the Federal Republic of Germany:
1949 - 1963: Konrad Adenauer (CDU)
1963 - 1966: Ludwig Erhard (CDU)
1966 - 1969: Kurt Georg Kiesinger (CDU)
1969 - 1972: Willy Brandt (SPD)
1972 - 1980: Rainer Barzel (CDU)
1980 - 1981: Franz-Josef Strauss (CSU)
1981 - present: Helmut Köhl (CDU)
President of the People's Republic of Korea
1980 - present: Park Chung Hee (United Democratic)
First this, then some status updates!