In my view, the best three speeches Barack Obama has delivered, in no particular order, are the:

(1) Eighteen minute, 27 July 2004 Democratic National Committee (DNC) Convention speech, that launched him onto the national stage in the United States.

(2) Eighteen minute 4 November 2007 presidential victory acceptance speech

(3) Thirty-seven minute 18 March 2008 A more perfect union, speech about the issue of race in U.S. delivered during Obama’s first presidential election campaign. Here is information about the speech and what prompted it.