And, of course, none of this is set in stone. Things can fall in and out of "iconic" status over the passage of time.
Basil Rathbone was
Sherlock Holmes to an entire generation of moviegoers, but I'm not sure that applies anymore. Modern audiences are more likely to identify Robert Downing Jr, Benedict Cumberbatch, or the guy on ELEMENTARY as Holmes, while others will surely be along to insist that Jeremy Brett is the definitive Holmes . . .
Maybe Nimoy should title his next book: I Am A