OK, I gotta weigh in on the side of free will here.
1) Two things that make humans different from other animals are our intellectual capacity and our ability to pause before an automatic response.
2) Our intellect does not run the show. Even though we have a dramatically increased mental capacity over other animals (dolphins possibly excluded:), it has been shown over and over again that our emotions and our survival instincts run most of our reactions, most of the time. The amygdala, a tiny part of the brain at the top of the spinal cord and the part that is focused on physical reaction to attacks, is one of the biggest culprits. It's actually not that different from the brain of a crocodile, yet it ends up contributing in our lives an awful lot when we don't really need it (i.e., when physical threats are not present).
Indeed, with most people, our intelligence spends most of its time justifying and rationalizing what "automatic reactions" we have already acted on.
3) We are not slaves to the neurochemicals in our bodies. There seem to be some in the population that have trouble producing certain neurotransmitters and such, and there seem to be drugs to help them, but the bottom line is that those chemicals are produced in response to our thoughts, and if we control and manage our thoughts, we can be our own masters. It's not our bodies that some of us are in enslaved to, it's our minds, and the thoughts we give life and credence to that do not serve us.
Even if our body has a tendency to come up short with one chemical or go heavy on another, many studies have shown that how we think has a huge influence on how our bodies do when we are struggling with such conditions - and how we train ourselves to think, and the thoughts that dominate our lives. This specifically applies to depression, where severe depressives have been found to react much better to a combination of talk therapy and drugs than to drugs alone. If it were all chemical, this would not be true.
4) Buddhism has some "religious" elements, but it also has many psychological elements. There have been several conferences where Western mind scientists have gathered to learn from Buddhist monks (including the Dalai Lama) about the Buddhist models of mind and consciousness. Buddhism has a focus on "being in the moment", as opposed to how many people react to situations by going into their past. In fact, most of our "automatic reactions" aren't in response to the immediate situation - they are responses to some past situation where we got hurt, and which vaguely reminds us of what's in front of us. By using "mindfulness" techniques (which many Western psychological treatments and stress reduction programs now use) many people have learned how to be more "in the moment" and less in the past.
So, to sum up: we are not slaves to our chemicals, we participate in what chemicals our body creates as far as behavior goes. If we take responsibility for our "re-actions" (responsibility - able to respond :) and we discipline ourselves to deal with the actual situation in front of us in the moment (rather than projecting our fears onto wheat we see before us) we can choose the right action (another idea that Buddhism works with a lot, coincidentally).
You've described a meat robot pretty well, sleepy, but I don't think you've addressed consciousness at all - not that voice in your head, etc. There are several models out there, and I won't try to pick one, but I suspect that that's where your question will guide you.
