"The first lie of fiction is that the author gives some order to the chaos of life: chronological order, or whatever order the author chooses. As a writer, you select some part of a whole; you decide that those things are important and the rest is not. And you will write about those things from your perspective. Life is not that way. Everything happens simultaneously, in a chaotic way, and you don't make choices. ...I really still do believe that even non-fiction genres like biography are at best perspectives of truth. The nice thing about fiction is that there is more freedom to play and ask "what if?", which, for me, is the fun part."
Comments from the NaNoWriMo message board on the subject of writing about real characters. Good points. Good food for thought.