On a TV show some years ago dedicated to discussing sci fi, one of the better sci fi writers was asked: "Who sits around and thinks about the future?" Without hesitation he replied, "Teenaged boys who can't get dates." Hence we dorm TV room denizens of any Friday night long ago. Dateless, dressed like nerds (heck, we WERE Nerds!), drinking Cokes and eating vending-machine Milky Way bars, and dreaming of excitement beyond the stars!
Arguably, the best part of the franchise were some of the movies; Wrath of Khan, Undiscovered Country, First Contact (I purposefully leave-out the whale-hugging one). "Enterprise" also started-out strong but faded by making the biggest mistake a space opera can make: It made space travel look boring (a criticism also leveled with some validity at NASA). The ship in "Enterprise" was far to smooth around the edges and viewers got bored. I think that's why Stargate SG-1 lasted ten years, plus two movies. It always had a ragged around the edges, last chance, crap! they almost killed us that time! excitement. Anderson's insistence that it remain entertainment and not preachy and that it be funny in spots also helped a good deal. That's why the sudden cancelation of the third movie and MGM's suddenly cutting its head off is so strange to the outsider. Just what happened, anyway?
Stargate Unwatchable killed it.
In retrospect, it wasn't very good -- especially when we compare it to what has been produced since then.
But back then, it was ground-breaking. Star Trek broke a number of taboos in TV entertainment, especially regarding the roles of women and race.
But, I agree with you about the movies being the best part. However, don't forget that the Wrath of Khan was a sequel to one of the TOS episodes: Space Seed. The role of Khan was even played by the same actor: Ricardo Montalban.