There have been good science fiction movies and TV shows going at least back to Metropolis. Of course, there is always Sturgeon’s Law, so we’ve also had ten times as many that were bad in one way or another. A few were memorably awful; a few are remembered as classics.
When it comes to fantastical material, I’m convinced books are best. Animation is a distant second, and live action can often be a mistake, depending on the material. Too much realism in visualizing the fantastic collapses the wavefunction of our imagination.
But our imagination is the best part, and it needs exercise!
British author and philosopher 
In every literary genre (in every type of art, really), there are classics that stand out and often participate in forming the language, or at least some of the territory, of the genre. That is part of what makes these works classics. (Lord of the Rings is an ultimate classic — all Medieval fantasy since is in reference to it.)
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