As Star Trek celebrates its 40th anniversary, you have been telling us which of the many incarnations of the science fiction franchise you prefer.
All five television series have been nominated, along with two of the films.
Read a selection of the arguments for and against each of them, and cast your vote to tell us which should be named the definitive version of Star Trek.
STAR TREK: THE ORIGINAL SERIES (1966-1969)
Narrative shortcomings and political correctness are unable to rob the background and setting of their revolutionary edge.
David Mana, Torino, Italy
Star Trek was created by policeman-turned-scriptwriter Gene Roddenberry, and followed the adventures of the crew of the Starship Enterprise.
William Shatner starred as Captain James T Kirk
According to the opening voice-over, they were on a five-year mission "to explore strange new worlds" and "to boldly go where no man has gone before".
It gave the series some of its best-remembered characters, from Captain James T Kirk to the half-Vulcan Mr Spock and chief engineer Scotty.
Star Trek was cancelled by NBC after two seasons, but a letter-writing campaign by fans kept it alive for a third year. It ended in 1969 after 79 episodes.
One of my best childhood memories. The series shaped many of today's inventions - just think about the cell phone!
Kishor Kafley, Mumbai, India
During a period of social unrest and change in the United States, Star Trek provided a dream for an entire generation. It preached acceptance of those who are different, [and] showcased the stupidity of bigotry. None of the other series recreated the message, nor advanced it to the next level.
Charlotte L. Ison, Riverside, US
It's really starting to date. The effects are laughable and the acting is not much better. Many episodes reference events that "happened" in the 1990's/early 21st century, which ruins it.
Dave N, Oakham, UK
Good science fiction doesn't comment just on "what ifs", but also on present-day conflicts. The Cold War during the 1960s was played out on the original series using the Federation to represent the USA and the Klingons to represent the USSR.
Theo, Toronto, Canada
STAR TREK II: THE WRATH OF KHAN (1982)
Rarely do you get a sense of the loneliness of space as you do in this film, and who denies shedding a tear for poor old Spock when they first saw it?
McKenzie, Greenock, UK
The second Star Trek film was made 13 years after the original TV series ended.
The film is based on a 1967 TV episode called Space Seed
It featured the villainous Khan, who was seeking revenge over Captain Kirk - now an Admiral - after being banished to the edge of the universe in a TV episode called Space Seed.
At the film's climax, Spock sacrifices his life to help his colleagues escape a deadly missile.
It has all the ingredients of a classic Star Trek story - a memorable villain, an exploration of the three central characters and their relationships, and an exciting journey through space. It's the small-screen version made epic.
Ray, London, UK
A sci-fi adventure film that can be enjoyed by newcomers and hardcore fans alike.
Steve Saul, Brighton, UK
It is the only one of the films which had a base in any of the series, that is to say it is the only film which continued on from one particular episode. Kahn just optimises vengeance.
Tadhg Clanc, Espoo, Finland
STAR TREK IV: THE VOYAGE HOME (1986)
Voyage Home has to get a mention as the least serious of all the Star Trek movies.
Douglas is right: The fourth Star Trek film, directed by Mr Spock himself, plants its tongue firmly in its cheek.
The film saw the crew of the Enterprise returning to present-day Earth
In the late 23rd century, a space probe threatens to destroy Earth unless it can communicate with a humpback whale - but the species has become extinct.
So the Enterprise crew travel back to 1986 to find some whales which they plan to send into the future.
During their trip, Kirk gets lost on a bus, Spock performs a Vulcan pinch on a punk, and Chekov is arrested by the FBI.
The leading actors realised they were all getting both chronologically and circumferentially challenged, and couldn't be taken too seriously any more, so went out for intelligent laughs instead - and it paid off.
David Gosnell, Surrey, UK
It has everything - comedy, action sci-fi and conservation.
Keith Hutchinson, Sunderland, UK
"You're from outer space?"
"No, I'm from Iowa. But I work in outer space."
It has to be Kirk!
Ben, London, UK
STAR TREK: THE NEXT GENERATION (1987-1994)
Patrick Stewart's Jean-Luc Picard raised the game for the whole franchise.
Wes, London, UK
Patrick Stewart led the cast of Star Trek: The Next Generation
Almost twenty years after the original series ended, Gene Roddenberry brought Star Trek back to television.
Despite a new crew, and a new ship, the principle behind The Next Generation was the same - to seek out new life at the frontiers of space.
This time, the crew was led by Patrick Stewart as captain Jean-Luc Picard. The Spock role is taken by Brent Spiner's character Data - an android who continually attempts to be more human. Comedienne Whoopi Goldberg had one of the recurring roles in the series.
It is the only Star Trek series to receive an Emmy nomination for best drama series.
While The Original Series defined the universe of Star Trek, I believe it was Star Trek: The Next Generation which best populated it.
Steven Zaretsky, Harmony, Florida, USA
Captain Picard was an inspiration for me.
The Next Generation was far too politically correct. Mankind was too perfect and you just didn't have the chemistry between the main characters that you did with Kirk and company.
Alan, Great Yarmouth, UK
The underlying message - do not fear what you do not know, welcome new races and continually look to better yourself - is a philosophy that is more relevant today then ever before.
Mike Brooke, Peterborough, UK
STAR TREK: DEEP SPACE NINE (1993-1999)
The characters face the consequences of their actions - something we don't see in the other series.
Leigh Judge, Perth, Australia
Deep Space Nine was a companion series to The Next Generation, with the action set in a space station next to a wormhole.
Deep Space Nine was the first series to be set on a space station
Unusually, it featured stories which developed over entire series, and dealt with dark, gritty themes unfamiliar in the Star Trek universe - such as terrorism, war and homosexuality.
The captain in this series is Benjamin Sisko, played by Avery Brooks, while the supporting cast included science officer Jadzia Dax and bartender Quark.
Because of its setting, Deep Space Nine was able to feature many more minor characters than earlier incarnations of Star Trek.
Deep Space Nine transcends the genre and qualifies as great drama.
Greg Moody, Staunton, Virginia, USA
It was dark and drew on what happened in the Earth's past - 1960s America, World War Two and terrorism.
Amar, Ipswich, UK
Deep Space Nine suffered from the characters being too "ordinary". I don't want my Star Trek characters to have the same failings as the people I meet every day.
Dave Barton, London, UK
It was a very gritty show. The characters have to deal with grey areas and the Federation is often on the wrong end of the war.
Manny Moreno, Valley, USA
STAR TREK: VOYAGER (1995-2001)
Where previous adventures sought new life and new civilisations, this little ship and her crew just wanted to get home. The concept alone tugs at the heartstrings and brings a lump to your throat.
Daniel, Saffron Walden, UK
As Daniel says, the fourth Star Trek TV series put its characters in a much more vulnerable position than its predecessors.
Voyager was the first series with a female Captain
The Starship Voyager is stranded light years from home after pursuing a rebel ship, and the series records the crew's attempts to get back.
The series features Star Trek's first female captain, Kathryn Janeway, played by Kate Mulgrew. Other characters include Vulcan security officer Tuvok, and Seven of Nine - a human female rescued from the evil Borg empire.
They adventured through new realms of discovery, both in outer space and inner space. Every episode brought something new and fresh to the front.
Jacques X, Frankfurt-am-Main, Germany
Voyager gave us three really strong female characters. My favourite was Seven of Nine. While some thought of her just as adding sex to the show, Jeri Ryan's acting really made the story of a young woman's search for her humanity one of the most fascinating.
Cath, Coventry, UK
You could see the franchise was running out of steam and needed a rest.
Keith, Columbus, Ohio, USA
Having a ex-Borg, the greatest enemy of the Federation, learn what it means to be human allows us to explore beliefs and emotions we take for granted.
Michael Hardy, Norwich, UK
STAR TREK: ENTERPRISE (2001-2005)
It gives the fans of Star Trek a beginning to the story, a new journey in human civilization.
Latern Colf, Toronto, Canada
Enterprise was a prequel to the original Star Trek television series, set in the middle of the 22nd century.
The cast was led by Quantum Leap star Scott Bakula
It follows Captain Jonathan Archer, played by former Quantum Leap star Scott Bakula, as he takes the first ever Starship Enterprise into space.
Archer makes first contact with some of the most famous Star Trek aliens - including the Klingons and the Romulans.
But viewing figures declined and Enterprise was cancelled after just four seasons.
It instantly dated the previous series and rendered them cheesy.
Tim Elson, Paris, France
It was the most bold Star Trek series - the ship didn't always work, ethics were often dodgy and the Vulcans behaved like disapproving parents.
Andrew Conway, Glasgow, Scotland
The premise of the show was in total contradiction to Star Trek's fictional history that had been carefully established before.
Steve, Nottingham, UK
It somehow captures some of the spirit and hopefulness of the original series.
Marianne, Helsinki, Finland
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