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!