I'll be honest as a Trekker. I haven't seen enough of The Original Series to make recommendations here. But, if you want to buy it I've provided the links below. I do know that I want to see it all and have seen several cool episodes. I simply can't stay up late enough consistently to watch it on the Sci-Fi channel.

I learned most about the crew from the movies. They're all interesting, especially James T. Kirk and Spock. Kirk is an interesting Captain and I believe would whip Picard's ass, but that's beside the point. He's different than any of the others. I believe he most resembles Sisko and Archer. They're somewhat non-standard Captains who get the job done under difficult circumstances. Spock made an excellent template for other future Vulcans to follow. Mr. Nimoy plays the role admirably. I also like the backstory of Nichelle Nichols (Uhura) overcoming racism and being one of the first popular black actresses. I'll really have a lot more to say about this series when I finally get around to buying these three seasons for myself.