I only ask these two because these are the only two series i think are worth talking about. Please explain your oppinon, so we can have a proper nerdy discussion.
OTS = "The Enemy Within" This is my favorite because i love seeing Shatner as the evil and wild Kirk, it provides some fantastic overacting as well as explaining perfectly how we need our evil side in order to counter act our pure good.
TNG = "The best of Both Worlds" (part 1 and 2) I absolutely ADORE this episode because for me this is the first episode where the Borg are truly explored as an antagonist (I know they were in "Q who" but they were just there without really going into any detail). It also provides some haunting imagery seeing Picard as a Borg, and the scene where they are turning him into a Borg and Picard sheds a single tear is one of the most dramatic scenes in sci fi history, this episode perfectly explains what Star Trek and all science fiction is all about keeping a living spirit in the midst of all this massive technology.
And now that my nerdy explosion of Star Trek love is over, I now ask you, what are yours.