Bill Keveney

USA TODAY

For all its influence, the original Star Trek ran for just 79 episodes, from its Sept. 8, 1966 premiere, "The Man Trap," to "Turnabout Intruder," its June 3, 1969 finale. (Was it a coincidence that in both episodes, a woman – or shape-shifting facsimile – was after Captain Kirk or one of his crewmen?).

In between were some classics, many quality hours and, of course, a few duds (Spock's Brain, anyone?).

Happy 50th birthday to TV's classic 'Star Trek'

But which were the best? USA TODAY asked those close to the original series for their favorites, and we offer a few of our own.

Adam Nimoy, son of the late Leonard Nimoy (Mr. Spock), cites two of his father’s favorites:

The second-season premiere, "Amok Time," in which Spock, suffering from a seven-year-itch of titanic proportions, takes Kirk and Dr. McCoy to Vulcan, his home planet, as he prepares for an ancient mating ritual. “That’s where he introduced the Vulcan salute” — the famed split-fingered open hand accompanied by the words, “Live Long and Prosper” — Nimoy says. The episode features a rare joyous outburst from Spock, after he learns that he did not kill Kirk during their kal-if-fee battle on Vulcan.

Another is "The Devil in the Dark," which features Spock sharing an emotionally searing mind meld with the Horta, a silicon-based cave dweller trying to protect her eggs from being destroyed by space miners. “That was very challenging for him to do, melding himself with another entity and expressing what that being was going through,” Nimoy says.

Star Trek 50th Anniversary

Rod Roddenberry, son of late Star Trek creator Gene Roddenberry, also recommends "Devil in the Dark," along with perhaps the most critically acclaimed episode, "The City on the Edge of Forever," winner of the Hugo Award, a top science-fiction honor.

In that outing, Kirk and Spock, searching for McCoy, travel back to the 1930s using a time portal and grapple with letting decent, innocent Edith Keeler (Joan Collins) die so that her anti-war movement won't result in Hitler's victory in World War II.

“It was just so different. It showed they didn't have to be out in space, didn't have to be on a starship, didn't have to have laser beams," he says. "Star Trek wasn't some spoofy, sci-fi thing. It was drama."

William Shatner, Captain Kirk himself, has a tougher time coming up with a favorite, because he says he hasn’t watched a lot of the episodes.

“One of my tortures is seeing myself on film, so I don’t watch,” he says. “So I take that the most popular episodes must be the ones that I would think are the best ones. So maybe "The Trouble with Tribbles" or something like that, but I don’t know for sure."

"Tribbles," known to even the most casual Trek fan, features cute, hairy furballs that just eat and procreate, adding tension at a space station occupied by both the Enterprise crew and their adversaries from a Klingon battle cruiser. The Tribbles prove their worth as good judges of Klingon evil.

Here are some of our favorites:

In "Balance of Terror", Trek introduces Romulans: ship captain (Mark Lenard, who later played Spock’s Vulcan father, Sarek, and then a Klingon captain in Star Trek: The Motion Picture) and the crew of a ship with a cloaking device that makes it invisible. The chess-like battle of wits between Kirk and the Romulan offers great twists and suspense, while dealing with prejudice as a crew member suspects Spock because of the physical similarity between Vulcans and Romulans. The episode is based on a 1957 World War II submarine movie, The Enemy Below.

"Space Seed" introduced Khan Noonien Singh (Ricardo Montalban) and his crew, the superhuman products of a genetic enhancement project on Earth, and raised one of Trek’s core questions: What happens when man creates beings superior to himself? Khan was such a popular character that he returned in Star Trek II: The Wrath of Khan and in the most recent Trek film, 2013's Star Trek Into Darkness, where he was played by Benedict Cumberbatch.

"Shore Leave" includes Alice and the White Rabbit from Alice in Wonderland as the Enterprise crew’s wildest imaginations come to life on an amusement-park planet designed by a vastly superior race.

"The Menagerie" and "Where No Man Has Gone Before" have historical significance. The two-part "Menagerie" repackaged scenes from Trek’s original pilot, "The Cage," which featured Shatner’s predecessor, Jeffrey Hunter, as Captain Christopher Pike, as evidence in a court martial proceeding against Spock.

"Where No Man Has Gone Before" was the second pilot, and the first episode featuring Shatner as Kirk, James Doohan as Chief Engineer Montgomery "Scotty" Scott and George Takei as helmsman Sulu.