I must admit I liked the original startrek. I also liked some of the settings of the later series (DS-9, Voyager), but I also never truly bothered to follow the series (chronologically or complete), because I got ultimately bored after a dozen eps or so, when nothing of the potential conflict in the setup between characters and surrounding was even remotely addressed or put to use.
The same goes actually for many of the sciencefiction series brought to tv or cinema in the last twenty years. Get me right: I *love* StarWars IV (and its potential), but that was *before* the rest of the saga; I love Eureka with its all nonsense take on scientists, and a few more (notably the original Battlestar Galactica and Bab-5, but again, "it's the setting, stupid." (to misquote Bill Clinton)).
However, when was the last time you saw a believe scientific and social different world set up on tv? The only thing I can spontaneously come up with is StarGate for a series, and even there it's mostly the original seasons with the earlier being the better, the Atlantis part lost most (if not all and then some) of its flavor, and Blade Runner as a movie.
SF author Charles Stross posted about the shortcomings of sciencefiction shows and movies in his online diary that brings these issues to a very clear point in terms of scientific and social world building for spellbinding scifi stories. His example is Startrek:TNG, and even if you don't agree with me (or like TNG to death), have a look at the quoted script excerpt for one of its eps, before the technical helpers filled in the gaps. It's a
thought-provoking read.