This hoary old chestnut crops up on a regular basis. Interestingly enough, I was rewatching Forrest Gump yesterday, and that film ends with Gump having a curiously wise epiphany on the subject, that "maybe it's both". I agree.

I also think that within the parameters of three dimensional space/time we have free will. But because God exists outside of time, he already knows the end from the beginning. So the answer is both. And yes, I know quantum physics makes people's heads hurt, so I'll leave it there...