I've seen all major Star Trek shows (ENT, TNG, DS9, VOY) with exception of TOS. I managed to get hold of TOS this week (Re-mastered edition) and just saw the first episode (The Cage Extended Version). I have to say, I am very impressed. To be honest, I put TOS off because it's the 60's with poor special effects etc but from what I've seen so far, it is pretty good and much better than I first thought. Are further episodes good like this?
What I don't understand is why Captain Pike is in command and I am not sure how/when Kirk comes into it. I guess I will find out soon enough.
I envy you. I wish I could go back and watch all the TOS episodes for the first time again...
But yeah, you are in for a great ride. TOS is excellent, and you have many, many more classic shows to enjoy.
And just remember: "The Cage" was the rejected pilot. The official first episode wth Kirk and crew is "Where no man has gone before"
And the footage from "The Cage" (the rejected pilot episode) was later incorporated into TOS's only 2-part episode "The Menagerie"
And on the current DVD/blu-ray sets, they have the episodes in air-date order NOT production order. That's why "The Man Trap" is listed as the first episode. It was the first episode aired on TV, NOT the first episode produced...