Re: Free from what, exactly?
@AlexV, the answer is both simple and complex.
Simple answer: Free from strict causality.
Complex answer: Not having free will simplifies lots of currently intractable physics paradoxes. Grandfather paradox of time travel? No problem, this was set to happen since Big Bang, and is not more paradoxical than that bang itself. Quantum entanglement? No problem, the tests carried on entangled particles were entangled as well, since the experimenters were pre-determined to carry out those exact measurements they did.
Having free will means we're (potentially) free from limitations imposed by our own laws and theorems we discovered: halting problem, Godel's incompleteness theorem, etc. Having it means also, that brain can never be replaced/simulated by a Turing machine, because it is a hypercomputer.
Also, there's an ethical distinction. Not having free will, a murderer will still stand trial and punishment (because his judges and executioners have no free will in the matter as well), but he shouldn't be considered any more guilty than the knife or gun he used.