Destiny?

When asked if he wanted to live in Rivendell, Strider replies honestly; that he would like to stay in the comfort and safety of Rivendell is a given, but it is not his destiny.  This raises a question: what part does destiny play in the lives of the characters?  And, if literature is an imitation of life, or a mirror image, if you will, then what does that mean about real life?  Thoughts?