Ten bests lists, and the like, should not be taken too seriously. Generally, a question such as “who was the greatest musician,” is really just a chance to talk about talent and accomplishment. The rankings themselves should be taken with a grain of salt. That is the way I feel about this list of the world’s smartest people. The list is inconsistent applying different criteria for different people, sometimes it gives IQ scores and other times it ignores them. Some of the IQs reported are really just guesses, and some, such as the claim that Cleopatra had an IQ, are based on very scanty evidence.
There is some reason to believe that creativity and cognitive ability (IQ) are different abilities. Thus, the inclusion of Shakespeare, despite his great artistic accomplishments may not be warranted. Also, why would Shakespeare be rated more highly than some non-anglophone literary figure, such as Tagore or Tolstoy?
If I were to draw up such a list, I certainly would include Godel and Cantor.
peakmemory 
Totally agree! “Smart” is one of those words very subject to interpretation. As articulated in Hank’s final words to Walter White in Breaking Bad You’re the smartest guy I ever met, and you’re too stupid to see.