At least we can all agree that the Beatles (or Radiohead) don't get to be number one on this list. Check it out and join the debate–the general criteria is, "most influential," not necessarily most wonderful. A random survey:
1) Abraham Lincoln;
16) Mark Twain (highest ranking purely literary figure);
30) Elizabeth Cady Stanton (the highest ranking woman);
46) William Lloyd Garrison;
52) Joseph Smith;
67) P.T. Barnum;
88) Enrico Fermi;
96) Ralph Nader.
Five of the top 10 were presidents–Lincoln, Washington, Jefferson, FDR, and Wilson. Anyone reading Reason for this past week will doubtless notice one very serious omission: the late Milton Friedman.
[UPDATE: I originally wrote that I couldn't tell if ever having been an American citizen was a requirement to make this list, but on further thinking about the list it seems as if it must have been–I don't see anyone on it who, to my knowledge, never became a U.S. citizen.]