All The President's Men is based on the book of the same name written shortly after the details of the scandal were outed. In fact, so contemporary were the events, that it rivals films such as The Social Network for the amount of damage that it could do to the reputations of people so high up.
Robert Redford and Dustin Hoffman play two Washington Post reporters who have just found out about the break-in in the Watergate building who discover that there may be more to the story than meets the eye.
All The President's Men covers many themes from this point of view - from freedom of the press, to high political dramas, to the story telling of contemporary events.
Unfortunately, as a 20-something in the 21st Century, I was unaware of the exact details (my only prior knowledge had come from a quick escapade around Wikipedia a few hours before watching the film) so the ending was very final.
Despite this, the story is told superbly - drawing the audience in from the start. Just make sure you do your background reading first.