I had to pick Dead Stop for a number of reasons. It's got a fun plot. Every cast member is featured, more or less. It has a classic sci-fi theme of a soulless machine that has to be stopped. And of course, at the end, when the space station is shown repairing itself after Enterprise leaves, shivers run up and down my spine.
Plus, love the Trip and Malcolm interaction, first when Trip convinces Malcolm to search for the space station's computer, and then later when Jon chews them out for doing so -- but wants to know what they found.
And Trip arguing with the computer voice about the shoddy workmanship repairing Enterprise!

Old enough to know better, but that's never stopped me before.