If we talking about additions to the list I would nominate Mad Max as well Arnold as the Terminator.
After Spock, Robby the Robot.
I debated between Spock and Darth Vader but eventually went with Vader. Spock might be more unique and interesting, but Vader is more iconic.
One anecdote that contributed to my choice: in the Star Trek reboot when the real Spock appeared on the frozen planet, there was an appreciative murmur from the crowd. But in Rogue One when Vader made his entrance at the end, people lost their shit.
I almost added The Terminator but honestly setting up a poll on a phone is a pain in the ass.
I don’t have a Hawai’ian print silhouette of Spock as my school page icon.
Spock was just one of several Vulcans, even in the original series. Vader was unique in the whole Star Wars universe.
Plus, he’s the only one you can identify instantly just by beginning to hear him breathe. There was one trailer, they didn’t even need to show him, they just added the sound at the end of the trailer.
Yabbut those people probably watch soccer and call it football.
/s
Darth Vader is the greatest villain in the history of film. That puts him well ahead of anyone else on the list.
He was the greatest villain in the history of film until he became a whiny pain in the ass.
Of this television and movie only list, I would go with The Doctor.
I thought long and hard about the poll choices. Not going to talk about off poll choices, because that would be another thread and we’ve already tried to go there a few times.
While pondering, I figured I’d look at a definition again to help clear things up:
And reading the third point “widely known and acknowledged especially for distinctive excellence” (emphasis added) I went with Ripley. Most of the other characters in the thread are indeed iconic, but they’re variants of much more common roles in the history of (science) fiction. But Ripley is an ‘everyman’ of a character, having been written (according to many places on the webs) to be cast male or female.
But she is most certainly female, and one without any of the heroic (or superheroic) skills, races, or talents of the most of the others on the list - she gets by with skill, brains, and grit. Solo can make the same claim, but the rogue with a heart of gold is not exactly distinct - even if the performance certainly is. And this role, this icon as it were, became the leading light for literally generations of female leads to come.
So that’s my reason, different emphasis on different portions of the definition will certainly lead others down other paths.
ISTM there may be a bit too many variations on The Doctor at this point so that the “icon” is different for everyone who could have supported that. Then again maybe that’s just me being a scarfie.
But yeah as mentioned, of these characters Ripley, Han and Kirk are really more like badass girl next door, magnificent rogue, and All-American-Hero tropes plonked down into a spaceship. (I’d say the Alien is more iconic of the Alien franchise.)
Vader was great.
Anakin was lame.
Lesson: Become powerfully evil and you will be awesome and feared and instantly recognizable around the world. 
And white.
Like Putin. 
Even the Doctor is doing mind melds these days.
Dude, no one has heard of Perry Rhodan. He’s not even iconic compared to other “olde time-y” sci fi characters like Flash Gordon, Buck Rogers, or John Carter.
Most iconic hast to be Darth Vader. His helmet is literally an icon
What’s a Nubian?
It’s Banky’s expression that really sells it here.
The TARDIS is way more iconic than any individual incarnation of the Doctor.
I’m not sure if this is what is meant by iconic, but I think more people around the world would recognize Vader than any of the other characters.