It is difficult to say about any of Martin Luther King, Jr.’s speeches, “This one is his best.”  The depth of content and delivery of his messages is so consistent every time he spoke.  However, there are messages that are more well known and more influential in the thinking, conscience, and behavior in the history of our nation.  One of those messages is his speech from the steps of the Lincoln Memorial in Washington D.C., delivered to over 250,000 who had gathered for the March on Washington in the summer of 1963.Here is the audio from the speech hosted on the Internet Archive:

A full transcript can be found at the American Rhetoric Top 100 Speeches website.  The video of the speech is provided by LearnOutLoud.com and is available on their YouTube page.