The problem with that sort of question, madam, is that the field's not only very large, but too varied.
There's about appoximately cirdca 190 countries in the world, and several different circumstances under which those countries exist, conditions they endure.
I suspect the ones that will be remarked upon as the "greatest" of this time, by historians not yet born, are George Bush and whoever all has been prime minister of Israel, both of them for their steadfast courage and persistence in keeping their own people alive despite strong opposition from many of their own; and Benedict XVI, for his vision of the world.
But the truth is, right now, May 2008, there just aren't a whole lot of leaders who inspire; such as Margaret Thatcher or Golda Meir or Lech Walesa. That happens once in a while, when the field's spare, but in times of Grave Crisis (we're only in a crisis right now, but it's trending that way), greatness emerges again.
