I have been thinking about the distinction between Star Trek and Doctor Who as emblematic of two kinds of sci-fi. I think this distinction already exists in science fiction studies, but I have been thinking about it myself for a specific reason I will get to.
In Star Trek the universe is essentially rational, and humanistic. The technology is basically believable. The anti-matter engine is a real thing you can create in a laboratory -- though at this point it is nowhere near cost efficient. The way the warp drive works has been thought out ahead of time by writers with a knowledge of hard science. The science has not been imposed after the fact, as it is in a book like The Science of the X-Men. People who major in science like Star Trek because they can get their heads into the technology and expand the basically sane ideas into whole books with charts, and blueprints, and all kinds of stuff. The world is basically human -- aliens are basically human, and on Star Trek are actually analogues to human racial stereotypes: The Klingons are war-like, and have a lot of wicker things on their homeworld; the Romulans are acetic, minimal designers, the Ferengi have one over-large body part and are obsessed with money; that race Diana Troy is from is emotional and are thus all kind of effeminate. There is always a non-human character who wishes he were human (Spock, Data, Odo, that hologram doctor guy on the ship run by Katherine Hepburn), because humans are the BEST. Kirk's grand embracing humanism will solve anything. It is all very American.
Doctor Who on the other hand does not even play at making sense. The ship looks like a police call box and flies through space. The Doctor is not at all human -- his whole human look is a facade -- and his assistant is thrown into an alien world (although, for budget reasons, the apocalypse is always centered in, like, Manchester). Opponents are vastly inhuman, like the Daleks, who only talk in spondees. Science makes no sense. The difference between the anti-matter engine on Star Trek and the sonic screwdriver on Doctor Who is really telling. This is also, for the most part, the world of comic books. I think the "British Invasion" of superhero comics can be traced back to Doctor Who fans invading a country of comic book people who grew up on Star Trek. They were just unprepared for that onslaught of insane madness, and people still debate whether Grant Morrison comics make any sense. Anarchy rules the day. But the British creators were tapping into something already there in comics, something many Americans had worked with and invented. As comedian Daniel Tosh put it -- "I can suspend my disbelief and accept that Superman can fly. But how does he fly FASTER?" Comics won't tell you.
Obviously I prefer the Doctor Who style sci-fi, because I prefer a focus on imagination and storytelling with characters, over realism, science, humanism, and allegory.
What has been on my mind lately is J.J. Abrams. Lost appears to be a show of the Doctor Who type, anarchic sci-fi featuring spirituality, magic and technology in conflict -- as opposed to a Dungeons and Dragons idea of magic as just a different kind of rational science with its own operating parameters (this is what Ellis says magic is in Planetary), or a spirituality that turns out to be nothing but a straw man for science to knock down (see the "Satan" episode of Star Trek: The Next Generation, or Stargate Atlantis, where religion turns out to be a big cynical scam like all the Star Trek fans were always saying in high school).
But with J.J. Abrams directing Star Trek I have started to wonder -- is it possible that LOST will end with a very rational explanation for everything? Will it turn out to be a show that only played with being a Doctor Who style thing, with Star Trek's mechanical heart underneath? I think that would bother me a lot. I miss Mr Eko. He was the voice of irrational spirituality, and a foil for Locke's paganism and when he died the show really lost something.