A few years ago I was lamenting the lack of quality science fiction and fantasy on television. It snuck up on me, but things have changed.
Firefly, though short-lived as a TV series and hobbled by risk-averse studio executives, had the wit of Buffy and the "western in space" conceit, much more over than Star Trek's "wagon train to the stars", worked. And hey! No sound in space! Looking forward to the movie a lot, even though the Reavers never did anything for me.
Battlestar Galactica treats the original concept with the gravity it deserves. Based on what I've seen so far, four of five episodes in (the wall of photos) and from what I've read is coming up, the writers will draw parallels between the destruction of the BSG colonies and the real world cataclysm of September 11. Olmos and McDonnell and most of the rest of the cast are wonderful, though the whole Gaius Bashir/Sixpot thread isn't doing it for me. The sensuality seems gratuitous and the religious aspect to their conversation should be interesting, but isn't.
Another show I've seen four-five episodes of is Lost. Lost is only tangentially SF/F, at least so far, though there are signs of miracles and mysterious goings on on the island. The format of one episode per story day stops the show from descending into Gilligan's Island where the survivors enjoy all the comforts of home constructed out of coconuts and paperclips. But it doesn't draw attention to itself as in 24. When I think about it, not a lot has happened yet, the arc takes time to unfold itself, but this is more than made up by a strong emphasis on characterisation.
I've only seen the first season of Dead Like Me but it's possibly the quirkiest, most appealing show of the four. I love its worldview - teenager cynical yet hopeful. Strange to be reminded of a series I've never even seen, but the phrase My So Called Death comes to mind. And Mandy Patinkin is always worth watching.