I've never gotten into Buffy the Vampire Slayer or its sequel series, Angel, mostly because both series have generally been opposite a show that I still watch and enjoy regularly, and by now both series appear to have a sufficiently established mytharc that I fear I would be at sea if I tried to come aboard now. When I've watched both shows, though -- I've caught an episode here and there -- I've found them to be intelligent and entertaining. Joss Whedon seems to know what he is doing with these shows.
And now, this fall he has a new one on Fox: a space opera series called Firefly. Apparently Whedon's concept is "Stagecoach in space", which sounds a lot like an early Gene Roddenberry description of Star Trek: "Wagon Train to the stars". Anyway, here's hoping that this new show finally gives something to look forward to on television on Friday nights, which has not been the case since the brilliant (in its first two seasons, anyway) but ratings-challenged Millennium went off the air.
(The Firefly official site can be found here, while a fan site [should a show that doesn't exist yet even have a fan site?] can be explored here.)