With references to everything from The Flash to James Joyce, from Greek and Egyptian mythology to Star Wars, Lost manages to fold myriad themes and parallels into sophisticated meditations on destiny, choice, and faith. But Lost also manages to be a show about Utopian visions and time travel, using its scifi roots to explore deep philosophical questions. And that's what great sci-fi does: it uses speculative worlds to examine our world, our humanity. Lost does all of this, and still maintains the pathos of a good television drama, drawing a wide audience into a show about time travel. It's not only great science fiction, but it's also a form of science-fiction evangelism.
Battlestar Galactica (remake)
The recent BSG reimagining is many things: a theological investigation, a mirror for our current politics, and one of the best space-war dramas of all time. But more than anything, it shows what can happen when you take a great premise — the last surviving humans flee through space after a robot-led genocide, searching for Earth — and take it seriously for a change. Almost everything that's great about this version of the show comes out of treating that premise with respect, and showing how our social institutions fare in that situation.
In many ways, space opera (and science fiction generally) gets divided into two camps: before Babylon 5 and after it. Show creator J. Michael Straczynski didn't just bring novel-style, long-form storytelling to the space western — he also brought more complex characters, a deeper mythology, and a sharper-edge social commentary.
This show spawned a meme ("The truth is out there") and created a whole cult following around the duo of FBI agents investigating the weird and the outright extraterrestrial in America. But over time, its paranoia became transcendant, suggesting a much weirder and more sinister world than you'd ever suspected was also out there.
Buffy The Vampire Slayer
Joss Whedon's best-known TV show started out as the quintessential heroic coming-of-age story, with a young hero who tries to balance her heroic destiny and a normal life — but over time, the metaphors grew richer and richer, and Buffy's search for herself kept going deeper and deeper. By the end, the show about the girl whom nobody would suspect of heroism at a glance turned out to hide even deeper secrets about who Buffy was underneath all that heroism.
A fictional US drama starring the equally fictional host of a real-life UK variety show? This short-lived 1987 spin-off from 20 Minutes In The Future did more than just vault over the fourth wall with glee; it also brought cyberpunk into mainstream living rooms, and created our lifelong crush on Amanda Pays.
Star Trek: The Next Generation
The first live-action Star Trek spinoff served up two embarrassing years of warmed-over crap, and then a funny thing happened — the stories started getting really good, and the characters became archetypes in their own right. The Borg and Q are as much a part of science-fiction lore as anything the original series served up. By the time it ended, TNG really was the only Star Trek for an entire generation.
Buffy may be Joss Whedon's best-known show, but this is his most influential, especially for science-fiction lovers. The saga of a crew of underdogs, survivors of an interplanetary civil war, doing dirty deeds to survive and trying to keep a low profile, managed to spawn some of the genre's most memorable characters in just a dozen weeks on the air. Nobody doing science fiction today — especially space opera — can fail to be influenced by this show.
One of the most iconic shows on television — period — let alone science fiction TV, Doctor Who uses its open-ended format (a man with a time machine) to tell a dizzying variety of stories. The one thing that never changes is the show's joie de vivre, in the face of horrifying monsters. The Doctor is the ultimate outsider and the ultimate hero wrapped up into one, and watching him fight evil regenerates a small part of us every week.
The most famous space opera of all time is also science fiction's greatest TV show generally. The U.S.S. Enterprise doesn't just explore strange new worlds and undiscovered civilizations — it explores us, our world, and the dilemmas we face as our technology outstrips our wisdom. Captain Kirk grapples with the Cold War, outwits authoritarians and zealots, and gives a little speech every episode about the human spirit — suggesting that all of our strange new dilemmas have solutions if we just follow Captain Kirk's rules to life. (And screw the Prime Directive.)