I have thought about this quite a bit.... I think the universe is a deterministic machine and that free will is an illusion. It's only the perception of free will that matters, so this conclusion doesn't "bother" me.
Think about it this way... if we had the ability to save the entire "state" of the universe and restore it to an earlier point in time, everything would play out exactly as it did before...the same choices would be made, the same seemingly random things would happen exactly as before: weather patterns, radioactive decay, activity at the quantum level etc.
Of course until someone creates a device that can save/restore the state of the universe, we wouldn't be able to test my little hypothesis. And even if we had such a machine, we'd have to be outside the universe so that our own observing mind is not restored with the rest of the universe.