SPOILERS FOR "SWORD OF SHANNARA" AHEAD!
Wait, no. SPOILERS FOR ALL THE STAR TREK MOVIES AHEAD!
Star Trek 1
Villain: The Voyager Space Probe... With an Attitude!
Shameful confession #1: I always liked the goofy "V'Ger" plot twist in the otherwise plodding Star Trek: The Motion Picture. If we're going to send pictures of prime numbers and naked people out into the reaches of space, we shouldn't be surprised if it comes back to bite us on the ass a few hundred years down the line. The basic concept would later be recycled for the amusingly dopey horror movie Event Horizon, which suffered from a dearth of Persis Khambatta.
Star Trek 2
He sticks bugs in Chekov's ear, he's responsible for Spock's death, he drives William Shatner to his peak of scenery-devouring histrionics, and he's got boss Labyrinth hair. Ricardo Montalban and his big plastic chest are the most formidable villain duo this side of Master-Blaster and the gold standard of Star Trek movie antagonism. Unbeatable.
Star Trek 3
Villain: Klingon Christopher Lloyd
Do you realize this is the only Star Trek movie where the Klingons are out-and-out bad guys? By #6 they're trying to forge diplomatic relations and stuff. Anyway, Christopher Lloyd tries his best, and he and Kirk have a great final showdown on the collapsing Genesis planet ("I... have had enough... of YOU!"), but the real focus of the movie is Spock's resurrection and the bad guy is too much of a weak Khan retread to make a strong impression. Plus, c'mon, it's Christopher Lloyd.
Star Trek 4
Villain: The Norwegian Whaling Industry
At first glance, this would seem to be the weakest Star Trek villain, but consider that Kirk and company had no trouble defeating a superintelligent space probe, the Klingons, and Khan, whereas the whaling industry is still among us. The entire Enterprise crew only manages to rescue two and a half whales from one damn whaling ship. However, the whaling ship only gets ten minutes of screen time and fails to distinguish itself in combat with a Klingon Bird of Prey, so meh.
Star Trek 5
Given that everybody in the Trek future seems to be some kind of agnostic secular humanist, they probably defeated this guy years ago anyway.
Star Trek 6
Villain: Shakespeare-Quoting Klingon Dude
Everybody forgets about #6, the Tom Clancy movie of Star Treks, and everybody forgets about this guy, played by Christopher Plummer. He's awesome! This is what you need in a Star Trek villain: an operatic obsessive played by a gravitas-laden actor who can quote from the Western canon without cracking up. If Patrick Stewart hadn't become a Star Trek hero, he could have been an excellent Star Trek villian.
Star Trek 7
Villain: Malcolm McDowell + Big Space Ribbon
Since this is the movie with two Star Trek casts (Original Flavor and Extra Crispy), they had to roll out two threats. First you think the problem is Malcolm McDowell (actor with gravitas) as a guy seeking eternal life (operatic obsessive), but then he summons his tag-team partner, the Nexus, one of those magic anomalies that puts you in a fantasy world where all your dreams come true and that's bad for some reason. Kirk gets to play cowboy on William Shatner's horse ranch, and Picard gets to star in Patrick Stewart's stage production of Dickens, but eventually they admit they have to get back to kicking the shit out of Malcolm McDowell, so they do.
It's not too bad as far as villainy goes, but McDowell's character isn't as good as Khan or the Klingon Shakespeare guy, and my favorite iteration of the fantasy-fulfillment trope in sci-fi is still that episode of Red Dwarf where Rimmer ruins the whole thing with his bad attitude and they all wind up buried in the desert and covered in jelly.
Star Trek 8
Villain: The Borg
You know why the Borg are the perfect Star Trek villains? Because they're the evil mirror version of the heroes. The Federation is a cooperative socialist republic; the Borg are a commie hive mind. The Federation embraces infinite diversity in infinite combinations; the Borg want to assimilate your uniqueness into their collective. The Federation is a technocracy; the Borg are technology gone amok. That's why, despite the silliness of adding a sexy dominatrix Borg Queen, the first all-TNG movie manages to deliver on the villainy. Cyborg zombies taking over the Enterprise are super scary; add unexplained bullshit time-travel powers, and even Picard starts freaking out. As corny as it is when Worf growls, "Assimilate this!" before blowing a bunch of the little white buggers into deep space, you totally high-five him with your mind. Admit it.
Shameful confession #2: Teenage Shaenon thought it was way hot when Data (her TNG crush of choice) got seduced by the Borg Queen, and Adult Shaenon secretly concurs.
Star Trek 9
Villain: Who Cares
Okay, it's some corrupt Federation reps who want to exploit a utopian planet that gives off Fountain of Youth rays. Man, I hate utopian planets where people live in harmony with nature and wear earth-toned fabrics. Utopian hippie planets are even worse than magic space ribbons that make all your dreams come true. Actually, the real villain in this movie is Troi, who shaves off Riker's beard, the only object with the power to make Next Generation good. But if the villains are supposed to be the evil Federation guys and their friends, they're even lamer than God.
Star Trek 10
Villain: Emo Picard Clone
Yeah, remember when I said Patrick Stewart could've been an excellent Star Trek villain? I meant actual Patrick Stewart, not a kid with a shaved head and a vinyl suit playing his wangsty clone. He even fails at killing Data, his one big evil deed, because they make a backup.
Star Trek 11
Villain: Aggrieved Romulan Miner
What the hell? This guy is like a conglomeration of all Star Trek movie villains. He's obsessed with revenge against the heroes like Khan. He squats in a vast, dank spaceship looking all tormented like the Picard clone, he's mad about his wife getting killed like Malcolm McDowell, and he carries a harpoon like the Norwegian whalers. (Dude misses a key Star Trek villain opportunity by not quoting Moby-Dick, maybe because Picard already quoted it in the one where they fight the Borg). Apologies to my lady friends who want his tribal-tattooed peen, but this one just didn't do it for me. I mean, he goes around in a black trench coat. Add a leather hat, and you've dropped from Star Trek villain to Star Trek fan. I'd rate him as low as God if he wasn't kinda hot.