I was not at all impressed with Firefly. It's idioms for the more primitive were too primitive (dresses from the 1800s???). It's Premise was awesome, but due to the mainstream audience, the writers were very constrained. Had it been done as an anime, I imagine it would have looked far more like Trigun.

Now, Farscape. This was a re-telling of the Buck-Rogers story, and it was done Freaking Well! They did not focus overly much on the technologies, which were mostly post-Singularity (as were many of the alien species), but due to the collapse of the civilization that supported that portion of the Galaxy, the Peacekeepers had become a force for malevolence and dystopic vision rather than the force for good which they began as.

I have never been able to enjoy Star Trek in any of its genres past TOS. The lack of obvious applications of much of the technologies, and the strict adherence to a dualist New-Age philosophy of consciousness really kept me away from the show. They occasionally had some excellent shows, but overall; I found that their lack of general AI, given the supposed power of many of their computers, and their lack of nano-tech based technologies (given the absolute necessity of nanotech for some technologies) was just appalling. The Medical technologies were also rather wonky. If they can regrow bone, and they can regrow nerves, and they can regrow skin, and they can regrow muscles... Why cannot they re-grow entire limbs.

Also, the silly rationale behind there were not more technologies like Giordi's eyes really made no sense.

IMO, the absolute Best Sci-Fi TV series in recent years has been the new BSG, and the upcoming Caprica, which will tackle a civilization as it approaches its own singularity and then fails to make it through the event horizon. Not due to having created unfriendly AI, but by having their AI corrupted by a psychopathic religious girl who manages to inhabit that AI. It should be excellent.