I like natural scroll so much I even use AutoHotkey on Windows to emulate the same behavior. Unfortunately, it reverses everything, so, say, volume scroll is reversed too. I'm sure there are workarounds about that.

Unlike some comments here, when I move from TrackPad to mouse, I still think of the scroll wheel as the document, so natural scroll makes more sense for me, personally.

The only thing I would get rid of in TrackPad is the "bounce effect" when you reach the Home/End of the document. Also, many documents are perfectly fit in the app window (e.g. Preview) but still the horizontal scroll moves them around, which is annoying (try opening a new PDF in Preview and use left/right arrow keys to move to next page; it scrolls the document horizontally slightly!)