I've never liked this line of reasoning. Is there some reason why you believe that "you" don't include all the bits that churn away below the level of consciousness? Haven't you ever had the experience of thinking about a problem for a long time without being able to solve it, going to sleep, and finding that you've gotten some new insight overnight that leads you to the solution? There's a lot of stuff that goes on down there below your conscious mind, but that doesn't mean that it's not part of you. I'm not chiming in on one side or the other in the "soul?" argument, but I am saying that "decisions seem to be made before we are consciously aware of making them" doesn't imply either "the human brain appears to be completely mechanistic" or "there is almost certainly no soul".
Actually, my argument in no way discounts the subconscious. My point is that free will, defined as an ability to make choices independent of the mechanical effects of the human body, does not appear to exist. To put it another way, when you choose to do something, you choose to do it because certain neurons in your brain fire, and those neurons fire as a result of environment and genetics. There is no separate self directing the brain to make choices - you are your brain, and your brain is a very complex biological computer.
And this helps explain the problem with the idea of a soul, as well. If you damage part of a brain, you will lose access to the functions that part directs. Lose certain parts, and you lose motor skills, memories, or abilities. Damage other parts, and you might have trouble with breathing, heartbeat, or paralysis. Damage enough of it, and you will cease functioning. If there is a soul, it seems very strange that the brain appears to encapsulate all that we are.
This would seem to make it somewhat self-evident that your thoughts, desires, and decisions are no more directed by "you" than your heartbeat, or your subconscious reactions. You have no choice but to think the thoughts you are thinking. What other thoughts could you think? If one really examines one's own thoughts and consciousness, one will find them, I think, rather ephemeral.
This doesn't take away anything from the wonders, pains, and joys of life, I think. But what it does do, as I imagine it, is reveal the silliness of thinking that we are static entities, or even continuous ones. Consider the following problem, if you will: suppose that, every night, every atom in your body was replaced by a (as atoms tend to be) completely similar atom, operating the same way. Would you still be the same person? And this happens, more or less, every ten years. Suppose that, one night, instead of replacing every atom, whatever process did this accidentally replaced you twice, creating two of you? It seems that both would have every right to consider themselves to be "you".
What if, every night before you were replaced, you lost your memory of the previous ten minutes? Would you still be yourself? Do you, even now, remember or store every ten or twenty minutes of your day? I doubt that you could tell me exactly what you did for a full day one year ago today.
What if your brain ceased conscious functioning for ten minutes before you were replaced, and then operated normally after the procedure? Why would this make any difference? If it does, then are those people who have been "dead" for ten or twenty minutes (as a result of extreme cold in drowning situations) different people? It is theoretically possible that we may some day find a way to put someone in thermal or temporal stasis. Since those people are not consciously functioning, indeed, are for all purposes "dead", does that mean that they are no longer themselves? Obviously not, I should think.
Thus, it would seem to be that one is not what one is composed of, or the form in which one exists (we do not consider pacemakers, implanted electronics, or other mechanical replacements/augmentations to be a threat to self-hood) that defines who one is. Nor does it seem to be whether we maintain continual conscious function, so long as we can resume it. This leads me to conclude that it does not matter if I continue in this exact same body, or am revived one thousand years from now, in regards to whether I exist. It is whether my memories, drives, thoughts, emotions, and all the other various bits of information go on, that defines whether I continue to exist. And that seems to me to be true whether I am flesh or machine, original or clone.