I'd say science AND religion.

But I see both as broken up into subsets that create most of the controversy. That is:

Religion is not monolithic. To be perfectly honest, I was taught growing up that, though there's little value in trying to make the distinctions to those who don't see the Christian faith as I was taught it, I was taught that religion was at it's best, merely a lame expression of the human end of the God/man relationship -- and that true Christianity was not a religion in the sense that religion is generally understood -- as a MEANS toward achieving the goals that the Christian believes God already accomplished (which is the worst of religion).

The science side of things is just as adulterated. Too many think they are talking science when they are merely delving in philosophy.

Ultimately, I believe that whatever scientific discovery -- true scientific discovery --- leads us to will also coincide with true "religion". I personally don't think that when we get there we will think of it as "religion". I don't think we'll have a problem viewing the science part that got us there as science, though.