I really dont understand some of the choices in this thread.
Wouldnt be one of the key things here that the character already existed in other media (books, comics, animation, real life history characters...) for it to fit what the OP is trying to say?
Some of the choices are great roles without a doubt, but they are doing original characters, and as the first actor doing that role they also had a big hand in creating that character and making it their own.
Yeah, they were written first on a script, but the audience watches them for the first time with that actor.
If for example, 50 years after an actor doing an original character in a great way, comes some type of remake with another actor that totally resembles the original one, that would be also considered an excellent choice for what the OP is saying.
Thats why i would only count here actors that were put into already existing roles. They were born to fit those roles because, even before cast, people in their head already said, he would be perfect doing this character. Or after watching the movie you think, wow, this actor is just like the real life (x character) I always imagined.