Wow there are a lot of people in this topic who don't know what they're talking about.
Anyway I think the debate is a good one, and I've been reading a lot of work on the subject recently (Blackmore, Crick, Dennett, the Churchlands, Metcinger, Ramachandran and Wegner amongst others).
I like the idea that consciousness is only a record of what's going on, rather than actually the place where decisions are made. Your brain makes the decision and then lets your conscious know (to attempt to state it in the most simple manner). The experimental evidence that backs this up (such as people with blind-sight) is pretty interesting, and I think makes the question of free will vs determinism a lot harder.
It's clear that almost all neuroscientists have rejected Descartes, and all the tangible breakthroughs in consciousness study have come from science, not philosophy.
Essentially it seems that we don't make conscious decisions, but that doesn't mean our brain isn't capable of making decisions, rather than simply reacting. It just means we become aware of the decision after we've made it.
So it really comes down to how you define free will. People like Daniel Dennett argues that of course we have free will, even though the decisions we make are completely due to our brain chemistry. It's still our brain chemistry that's making the decision. I tend to agree with this sentiment. I think the whole debate around the question comes from the false idea of Cartesian dualism, and we can now see that that's false. The idea that we don't have free will really comes from the idea that the physics of our brain controls our mind, but I think most cognitive scientists these days would agree that the physics of our brain is our mind. You can't separate those. If our brain can make decisions, we can make decisions, and we know that our brain can make decisions. Reactionary decisions are still decisions.
I think the idea that things can happen without a reason is ludicrous. Obviously there are reasons why we make decisions, that doesn't mean we don't have the potential to make a different decision.