Of the forty-two* men who have been the President of the United States (and I mean under the Constitution; so, don't even bring up the presidency under the Articles of Confederation), four have had alliterative names. Interestingly, so fond are some people of alliterative names that two of those four men used their middle names as their first names in order to have an alliterative name. Also, two of those four men had Wilson somewhere in their name and were the only two presidents to be named Wilson in any form.

Thomas Woodrow Wilson
John Calvin Coolidge, Jr.
Herbert Clark Hoover
Ronald Wilson Reagan

*President Cleveland may be counted as both the twenty-second and twenty-fourth presidents, but he was still only one man.