How can you all be sure that the man in black is evil incarnate? Maybe he really is the good guy who wants to free everyone and Jacob was really the bad guy. After all, all we have really seen of Jacob is he and his followers being manipulative jerks all the time. The men at the temple kidnapped all the children who survived the crash, as well as many of the tail section people, such as Cindy, who now appears to have been brain washed. Also, seems Jacob is in the habit of giving people hard choices and not allowing them to ever leave the island again (such a Doogan not being allowed to leave the island in exchange for his son's life). If you ask me, the "good guys" really are not all that great. If fact, we've seen and heard all of them doing far worse things than we have ever seen Darth Locke or his followers do. Keep in mind, the side you are now calling good have consistently been the bad guys for the majority of the shows run.

In fact, Rousseau was the only character I can think of that may have been under his influence since the beginning of the show, and while she had some mental stability issues, she always seemed far better intentioned than any of the island's other inhabitants, and more helpful and friendly to the castaways to (other than that the time she kidnapped Sayid and later Aaron).

Not saying I am convinced that this is how it is going to pan out, as I am actually feeling mostly certain that Jacob's side is suppose to be the good side. But looking back and putting it all in perspective... these "good guys" are complete bastards, Jacob included.