I have never watched more than the first episode of TOS.
I am ready to mend my ways, so I've come to the experts.
So tell me, which episodes are the very best?
I suppose if I am going to slag off on other people's lists, I should step forward with a list of my own.
Lisa, a lot depends on how big you want your list to be. If you pinned me down and asked me for the VERY BEST episodes, my list would only be 3:
City on the Edge of Forever
That's probably in ascending order of quality, and coincidentally in inverse chrono order, but I'd suggest watching them in that order.
If you want to take a leisurely tour thru the better stuff in season one, in order; then I would give you this list of 12:
Enemy Within *
Dagger of the Mind
Corbomite Maneuver *
Balance of Terror *
Taste of Armageddon *
This Side of Paradise
Devil in the Dark *
City on the Edge of Forever ***
The ones marked with a star are my top 5 of season one (plus City of course).
I could also give a season 2 list, but one season would certainly get you started.
One thing I especially like about Charlie X, Mudd's Women, Dagger, Devil, and I'll throw in Court Martial & Conscience of the King too: they are the episodes that give you the best sense of what the galaxy of the Federation is like. A lot of Trek has the crew out in unknown space, interacting with aliens and hostile environments; those episodes have the crew interacting with other earth ships or settlements or starbases. It's interesting seeing them among their peers.
(Taste of Armageddon has really grown on me in the past few years. I used to dismiss it as kind of an unremarkable episode. Nowadays I tend to think it's almost THE perfect example of a basic "good" Trek episode. Not an awesome episode, nowhere near among the best ever: but a perfect example of what a "good" Trek episode is like. It does a lot of things well. Plus it has Barbara Babcock, and the "I will not kill – today" speech.)