These are my top favs...I couldn't stop at 5...its illogical to limit oneself!!!

"Mirror Mirror" Spock w/ a goatee...totally cool. Kirk porks both versions of Lt. Moreau.

"Trouble With Tribbles" My fav. Klingon, DaHar Master Koloth was featured in this one.

"Space Seed" Khaaaaaaaaaaaaaaaaaaaaaaaaaaan

"Balance of Terror" shows my fav. targets...Romulans

"Amok Time" Spock in rut...fascinating.

"The Conscience of the King" a view into Kirks past and he tries to pork a murderer.

"Errand of Mercy" first Klingon episode, with the DaHar Master, Kor.

"Journey to Babel" Spocks parental units, (Mark Lenard played the Rommie in Balance)

"The Day of the Dove" DaHar Master Kang was the feature Klingon in this one.

"A Private Little War" Hot medicine woman, a Klingon, and the Mugatu...how cool.

"Elaan of Troyius" The Klingon D-7 battle cruiser makes its first appearance. Kirk tries to pork a queen.

"The Enterpirse Incident" Hot Rommie commander and Kirk as a Rommie.