No, depends who you asked. If you asked Star Wars/Harry Potter freaks, they would say that. But some others would mention Danny Elfman (Batman, Spiderman, The Simpsons, etc.) and some more would mention Jerry Goldsmith (Alien, Poltergeist, Star Trek films, etc.). James Horner is the one behind Titanic and he probably is known by quite a few people.
Among Videogame composers, I usually read more about Mr. Kondo and Tommy Tallarico.