Star Trek: The Next Generation

Essential, and the standard recommendation for where to start the whole franchise. It is set eighty years after the original series with an entirely new crew, requires nothing before it, and is the version of Star Trek that most of the culture is actually referring to.

The format is its strength. Almost every episode is self-contained, built on a single premise examined from several angles, and resolved by people in a room arguing about the right thing to do. The best of them are among the best television science fiction ever made: a trial over whether an android is property, a man who lives an entire other life in twenty-five minutes, a first contact told from the aliens' point of view, an officer tortured into agreeing that there are five lights.

The warning everybody gives is correct. The first season is poor and the second is uneven, hampered by a writers' room in turmoil and by a captain who had not yet been written properly. Start at the third season if you want the show at strength, or watch Encounter at Farpoint for the setup and then skip ahead. From the third season to the sixth it is remarkably consistent.

Patrick Stewart is the reason it became what it did: a captain who is a diplomat and an archaeologist rather than an adventurer, visibly uncomfortable around children, and willing to lose an argument. The two-part episode that ends the third season is the most famous cliffhanger in television science fiction and still works.