I think that inherited genes and location only plays a smaller part - but it depends on the person. For a normal western person my personal belief is that it is less than 10%.
I am a strong believer in free will and it's what makes us so different than animals. Animals have insticts and very little free will.
The thing is that if you believe in free will you have more free will as you will change your way of thinking. At least I believe that.
Back in 2007 I wrote an essay "Life As a Game of Chess": http://www.jimwestergren.com/life-as-a-game-of-chess/