[dtw]

The "good vs. evil" movies always get me. Without thinking about your question for hours, the most impactful movie I can think of is "No Country for Old Men".

It nails the classic good vs. evil bit, but also throws in all sorts of questions about causality. If you watch the scene with Anton Chigurh, the gas station owner, and the quarter a few times, and start to really think about it, your head will explode.

That, or I'm just easily entertained. Which tends to be true.