For people of a certain age Cosmos is legendary. It changed the way we think about the world and the universe, and it certainly changed the way TV presented science to the world.
Dr Carl Sagan was not only a super intelligent man, but he could communicate difficult and complex ideas easily to the masses.
Cosmos is simply the greatest science documentary in history. Sagan not only tells us about the story of the universe, but of the creation and formation of Earth, the Solar System, and of us. He travels through time and space in his spaceship of the imagination (a dandelion!) and also reflects on humanity's successes and mistakes when it came to enlightenment.
Cosmos was for me as a young child growing up a seminal moment of TV. To finally get to own it on DVD was amazing.
I cannot recommend this enough.