Currently in the 2012 Olympics:
China has the most medals (42 medals) 3/8/12
(Extra info: Britain currently 3rd place)
However, not sure about the entire Olympic games
The US won the most medals in the 2012 Summer Olympic Games in London.
As far as total medals go, England has won their most Summer Olympic medals in athletics and their most Winter Olympic medals in figure skating.
China took most gold medals, and USA took the most medals.
Phelps
The United States.
Norway has the most overall out of every winter Olympic games.Though the United States of America has the most medals in the winter Olympic games in Vancouver.
China won the most medals.
Michael Phelps
Norway.
34
USSR
USA won the most Medals with 104 and 46 Gold Medals