Well, Farscape was the best show on television, but I'm afraid you missed the boat on that one. So did a lot of people, which was the problem really. Produced by Jim Henson's creature company, the show had outstanding production values. The stuff didn't have that sleek, expensive look you expect from any recent ST shows, but it was very imaginative. Picture "The Dark Crystal" as a sci-fi TV show.
Sadly, Farscape was too good for it's own good. It had strong plot development throughout the entire four-year run, and intricate character arcs. So anyone who hadn't been watching couldn't just jump in and have any idea what was going on. And since Sci-Fi, like any good network, doesn't care as much about the quality of a show as the quantity of its viewers, it got cancelled.
Sometimes I blame Stargate, but that's just petty, I know.
I can't believe, though, that several people have rated the best sci-fi of all time and forgotten the best TV show ever, "The Prisoner"! This show was great! Psychological philosophy disguised as entertainment! And darned entertaining too! If any of you haven't seen the show in its entirety, I command you to rent it or buy it immediately and go mend!