I think this debate showcases one of the best things about Butcher's source material as well as the awesome job the Evil Hat guys have done in representing the game world. Simply put: we don't know the answer to this question. It's not "free will or good vs. evil" the truth is somewhere in the middle-- a middle ground each group and/or GM will find for themselves. It really depends on what kind of stories you want to tell, and most especially what kinds of baddies you want to put your PCs up against.
If you want to focus on the redemption angle, pit your group against Denarians, those possessed by demons/ghosts/etc, or even a warlock not so completely gone that they can't choose redemption (Molly Carpenter, anybody?). This is a much more "shades of grey" choice. If you'll notice, all of these baddie types have some kind of interface with mortal humans.
If you want to focus on good vs evil, go with vampires (all four types, depending on how they're portrayed), ghouls, non-Denarian Demons, Outsiders and dragons. All of these are far more "black-and-white" morality, because they don't have as much to do with mortal humans (except as food, in most cases).
Basically, I think the game can support both kinds of stories about the Creator (as the source material tends to name Him), even both kinds of story woven between each other for a more full-spectrum kind of experience. I just believe that the PC isn't the only thing to look at in terms of how the character plays-- just like in real life, it's the actions people take in relation to their environment that define them best.
Just my opinion, and trying to take some of the theory in the earlier debate and make the rubber meet the road.