Penny Lane, I like them all, but I'll list my favorite Season One episodes:
"The Enemy Within"
"The Menagerie, Parts I and II"
"Balance of Terror"
"The Squire of Gothos"
"Tomorrow Is Yesterday"
"Court Martial"
Joan Marshall (Lt. Areel Shaw, prosecuting attorney) is gorgeous. But a true girlfriend would have recused herself from prosecuting Kirk. So I don't care much for her. Kirk should not have kissed her on the bridge. He should have transported her to some frozen planet thousands of parsecs away.
"Space Seed" Bravo, Ricardo Montalbán! Great acting!
"This Side of Paradise"
"The City on the Edge of Forever" Heart-wrenching conclusion. The expression on Kirk's face both at the accident scene and on the bridge sums up the meaning of Captain James T. Kirk.
Dr. McCoy: You deliberately stopped me, Jim. I could have saved her. Do you know what you just did?
Spock: He knows, Doctor. He knows.