we have free will in that our minds can make decisions on their own, albeit very influenced by external stimuli. freedom of choice however...as all the sciency-wiency stuff thats been posted has shown, actual free will is pretty much against the laws of physics (this is me qualifying myself by saying that im far from a scientific philosophy professor). our brains are simply a very complex from of central nervous system, it exists to guide us through life by interpreting the outside the world as best it can so we can use or avoid things to survive. instinct, emotion, and are just very complex forms of logical interpretation, 2 of many subconscious processes we are designed to follow, not understand. because we are consciously unawares of the deterministic nature of emotion, and because it influences every thought in some way, we naturally developed the illusion that we are choosing what to do with our lives, instead of just following a very very complex logical interpretation. 'choice' is merely the psychological lie we have invented for ourselves trying to consciously understand and accept these complex thoughts in action. 'deciding' is simply these thoughts running through the possible consequences before arriving at the action it deems most satisfactory.
its not that every single action anyone's ever done has been prophesied from the beginning of time, its just that whatever we do 'decide' to do is independent of any causality-breaking naked singularities in our brains. choice implies that we can do something entirely unpredictable, and scientifically im pretty sure predictability is like, the foundation of the entire universe. human psychology is just another from of autonomous reaction; a very complex one, but our minds dont somehow operate on different laws of nature; our choice is simply a relatively unique form of autonomous reaction.