For some reason I keep coming back to "The Ultimate Computer" over and over. It's a really tautly written "bottle" episode, with a hammy-but-good performance from Shatner, an amazing performance by William Marshall as Daystrom, and that really great scene with Kirk and McCoy as they toast "Captain Dunsel." Of the various "Kirk talks a computer to death" episodes, this one is possibly my favorite, in part because the computer Kirk has to talk down is the one running his beloved ship.