I thought Next Generation was pretty good, but everything after that got too dam wierd.
The original series was quite groundbreaking for it's day. It amounted to social studies in space. And actually, even though it was "The Federation", you could see alot of regular American values in it.
I think it was on Thursday nights, but it's been awhile, thats for sure.
(Showing off my nerdiness) The episode The Omega Glory near the end of the 2nd season of the original series was based around a battle between the residents of the planet, whom I believe were called the Yangs ("Yankees") and Kohms ("Communists"). At the end of the episode, Kirk gave a large dissertation on the US Constitution (which the Yangs consider to be a supreme lawgiving document). Patriotic episode indeed.
I still watch The Classic Series and all the Star trek incarnations (shortened to TOS, as TNG is short for The Next Generation). I grew up with TOS though, it is what got me interested in space, astronomy, science, physics and theoretical physics.