I actually made a list of six episodes that I’m going to use on a friend later this month.
- Balance of Terror
- The Galileo Seven
- Space Seed
- The City on the Edge of Forever
- The Ultimate Computer
- Amok Time
I wanted to find the best episodes with a low cheese-factor, since the whole reason my friend has been turned away from watching TOS is its corny nature. He actually likes TNG, but hasn’t given TOS a chance. I told him that he would like the TOS movies, but that he has to watch some episodes first. As you mention, the emotional stakes would be higher, in addition to the fact that TMP isn’t a good introduction to the characters, and I want him to watch that too.
“Balance of Terror” and “The Ultimate Computer” are on the list not only because they are two of my favorites, but also because they contain similarities to TWOK, so they help be a lead-in to the movie’s action, and the theme of Kirk feeling outdated.
I included “The City on the Edge of Forever” “Space Seed” and “Amok Time” for the reasons you mention. But “Amok Time” really only gives you Vulcan culture, and not a whole lot of Spock himself, and that’s why “The Galileo Seven” is in there.
I wasn’t too worried about introducing Sarek, but that may change if he’s willing to watch more episodes. Depending on how much time he wants to invest in the show, I would also put “The Doomsday Machine” in the ‘must watch’ category, as it’s another of my favorites.