Interesting question. If you ask me, I believe that there IS free choice. I back this up from several points. First, I hold a deist view of creation, and while I may differ from traditional deism in that I do not believe that God is dead or doesn't care, it is pretty evident that He does not interfere in this clockwork universe. The arguement may be made, then, that a clockwork universe is just working out it's mechanisms according to the laws that run it, and all our actions and decisions are just manifestations of the cooling of the universe, and as such we do not have free will any more than a cog in a clock chooses to rotate and interact with the other components of the clock.
I think the key to free choice is found in quantum physics. All of the macroscopic universe is just a manifestation of average probability. On the most microscopic level, physics operate under different laws and is much less clockwork. Many studies that can be repeated in laboratories show that the state of the universe and reality is dependent on human perception/choice. Light is inherently both a wave and a particle, a paradox, being that one cannot be both. If you do an experiment, and look for a particle, light will be found in particle form only. If you look for a wave form of light, only a wave form will be found. The state of the most basic form of existence, energy, is dependent on the choice of the human mind to decide what form it will take. This shows a property of the universe that is not clockwork and mechanical, but interactive with intelligence and choice. There is also a randomness to quantum physics that throws the whole clockwork universe theory into a ringer. As I mentioned earlier, the macrospopic universe is a manifestation of probability. At any given time, an infinite amount of random quantum actions are decided by chance. Does the electron move left or right, up or down, does it combine with a proton, does it exchange itself with another electron from another atom? All these actions are completely random. We can predict that out of probability, 50% of a radioactive substance will decay within a given time, (halflife). But the actual process of decay is far from clockwork and organized. Nothing is so set as to know that "this atom will give off one electron every 12 minutes." Instead, we know that on average, this particular type of atom will on average give off so many electrons over a period of years. They may be evenly spaced out, or they may all be released at the begininng or end of that time frame. With this randomness in the universe, the argument that our percieved choice is just a manifestation of the predestined workings of a machine falls apart.
I know that was rambling and hard to follow. I hope I made at least a little bit of sense. If you want, I will get you some more concrete examples of the phenomena that I was trying to describe, or mabye describe them a bit better.
Peace
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