Personally, I would like to add fictional Presidents to the celebration. Here are my favorites as depicted in movies and television.
James Marshall in Air Force One - Harrison Ford was a tough, ass-kicking President who took matters into his own hands when his airplane gets hijacked in this farfetched but completely enjoyable action flick.
Josiah Bartlett in The West Wing - This television series started out with a focus on the people working behind the scenes with the President, but Martin Sheen soon took the spotlight with his excellent portrayal of the idealistic leader.
President Beck in Deep Impact - Morgan Freeman displayed dignity and reassurance in the face of armageddon (no pun intended referencing the similarly themed movie of the same name) when an asteroid is about to annihilate all life on Earth unless astronauts can figure out a way to divert its course.
Thomas J. Whitmore in Independence Day - Bill Pullman gave the speech of his life trying to motivate the survivors of a hostile alien invasion. It may have been corny, but it was one of the many memorable moments in this classic popcorn movie.
Mackenzie Allen in Commander in Chief - Although this was a short-lived TV series, Geena Davis made us believe that we might one day see a female President.
David Palmer in 24 - There have been a number of Presidents in this action-packed television series, some incompetent, some traitorous, but none have been more heroic than the one portrayed by Dennis Haysbert.
Merkin Muffley in Dr. Strangelove - Peter Sellers played three distinct roles in this Stanley Kubrick masterpiece, and his President is one of the funniest ever. "Gentlemen! You can't fight in here! This is the War Room!"
I've left out countless others. Which ones are your favorites?