In but not of the world

How do as believers do what we're called to do to be in the world but still manage to not be of the world?

Im reading a book about engaging the youth culture so we can relate to them. The book basically advocates that we need to be watching the music that youth listen to and watching the movies they watch. Reading the books and websites they read... This way we can unerstand their culture and then someday speak to it when they need to understand the lies that are presented or recognize when they feel lonely, hopeless, and lost.

I agree. And i could listen to just about any music and not fall into sin. But there are a lot of movies out there that are just filled with straight up porn. I cant process that well. At all really. And i certainly cannot condone watching them to understand youth.

I once saw requiem for a dream. It did not make me a better person. Sure it was a grotesquely accurate portrayal of the lives of heroin addicts. Ive known many since working at a heroin rehab center in hong kong. But i didnt learn anything new by watching this movie.

I just got totally 'slimed'

Where do we draw the line? Are there some people who can watch any movie and not fall into sin in the way cursing in songs doesnt really affect me?

How do we understand the culture if engaging it leads us to sin?

Im sure there is a balance... But where?