The composer John Williams (Star Wars, Jaws, ET, etc…) has said that the best composers are thieves. I think what he meant was that there is no need to be totally original. All you truly need to do is take an existing idea or concept and adapt it, refine it, tweak it, or use pieces of it to create something new and different. Obviously you should not take something and plagiarize it. But, you do not need to invent a whole new thing. John Williams himself is a good example. He used the work of Erich Korngold to create the theme for Star Wars (Listen to the main theme from the movie "Kings Row"). This concept applies across the arts and in any endeavor where ideas are paramount (which is everything). Next time you need an idea, take an existing one and mess with it till you come up with something new or different, Hey it worked out pretty well for John Williams.
What do you think?