Star Trek VI: The Undiscovered Country (1991)
In my personal opinion, this is the second best of the original series cast movies. Wrath of Khan is a fantastic movie, and it is hard to argue with the idea that it is superior. I mean, you have Ricardo's pecks, Shatner's best acting job, and an immensely compelling storyline. How can you compete with that?
For starters, you make Christopher Plummer a Klingon with an eyepatch bolted directly into his skull. Mr. Plummer does an amazing job in this movie as he manages to come across as both a bloodthirsty Klingon and an armchair intellectual (not an easy task after Doc Brown did his Klingon). His style is unique in the Klingon lexicon, and he manages to be both intriguing and menacing in a way not too dissimilar from Khan, but he comes off as smarter, less meniachal, and more grounded.
Then, you add the crew. When the second movie was made, the crew had established their characters, but they only had one movie under their belt. That first movie was pretty terrible, and they redoubled their efforts to make the second one better. The director of the first movie was dropped for someone who knew what he was doing, and the special effects budget was clearly stepped up. In this movie, the crew has even more experience, they were rebounding off the horrifically bad 5th movie, replaced the director with someone who knew what he was doing, and stepped up the special effects. Really, their biggest issue is that they're a bit past their prime for hopping around the galaxy.
The director of the last movie was William Shatner. He should never have been allowed to do it. The director of this movie was Nicholas Meyer who also directed... The Wrath of Khan. Clearly, the intent was to recapture the magic from the second movie, and Mr. Meyer's intent was to one-up his previous Star Trek effort. He also co-wrote the story.
Oh, and we get rid of the two attempts at the same Vulcan woman. Instead, we bring on Kim Cattrall as a new version of a new Vulcan woman. Really, I don't know why they bothered creating a new character. It might even have been better for the storyline if they had stayed with the old character - it's not clear why they wouldn't have.
So, we have political intrigue, but it's not the kind of Bajoran in-fighting that Deep Space 9 brought to us and made us long for the days of Tribbles and the simple pleasures of Picard shouting, "Tea, Earl Grey, Hot!" Instead, we have a conspiracy to start a war that catches the Enterprise and its crew in the middle. I don't want to delve too much into specifics, but the complexities are just enough to make it interesting, but not so much that it is too hard to follow.
Direction was stellar
Story was fantastic
Dialogue was great
Special effects were amazing - even after all this time
Acting was great
Even the action wasn't that bad