1980s League of Extraordinary Gentlemen
I'm a bigger fan of the comic. Really, I'd like for people to be able to represent themselves as anything from one of the Breakfast Club to John Rambo to a T-800 without the rules getting in the way.
I'm going to say that acceptable sources are movies, books, video games, and television shows set in the 80s. Comics, not so much, unless they also had a movie or TV show - there's too much "baggage" with their universes otherwise.
Superman, Supergirl, Batman... they're the only superheroes implied by their movies, and that's fine. But taking the same characters from the comics really inflates what's out there.
(I am going to say that Superman himself is reserved for reasons of Plot, and possibly Supergirl as well.)
In terms of what I'll be looking for: Variety. There are a lot of brawny action heroes played by Stalone, Chuck Norris, Schwartznegger, etc, and I don't see a reason to take more than one of them when there are so many weird and interesting characters to choose from, like Tattoo from Fantasy Island, Chunk from the Goonies, or, I don't know, Mr. Belvedere.
Other details: I'll pick a specific year to set the game. Part of character creation will be extrapolating what's happened to your character between the air date of their medium and the start of the game.
Example: Danny was 6 when the Shining took place in 1980. If we set ourselves in 1988, he'll be 14.
Further, if a property exists as a book and a film (as in the Shining) we'll use the dates and version of the latest adaption.
So the system involved will have to be able to deal with characters of vastly different capability seamlessly, without letting players feel less useful for playing more down to earth characters.