I hear from people regularly who are interested in making a move to the country and want to know how much land they need.  This question has also been the impetus for many discussions around the fire.  There is no right answer, as everything depends on the land and what you want to do with it.  That being said, Leo Tolstoy wrote a great story on the topic title How Much Land Does A Man Need (short version of the story from Wikipedia is here).  In the end, not so much.