Hmm. Well, he liked Star Wars quite a bit, and while his tastes lean towards action/adventure, he can also appreciate romantic or psychological tales if they're fast-paced and executed well. We have very different senses of humor, so a dramatic episode might be preferable to a lighthearted one. He really doesn't watch a lot of TV, but he's a gamer and enjoys being able to think and interact with ideas.
Not sure if that helps? I think he'll be satisfied with almost any episode; I just want to make sure I don't foil the opportunity if another episode is better. I made him promise to watch one with me after he couldn't pick out Kirk in a photo of the crew. :P If he becomes a Trekkie, all the better, but I'll settle for basic competence!
After reading your post, if I were you, I'd settle for What Are Little Girls Made Of?, Catspaw or That Which Survives.
What Are Little Girls Made Of? is IMO the only great episode of these but the other two has some elements that might appeal to your dude.