As a long-time X-Files fan (which never scared me) I was surprised to find myself really frightened by Supernatural. And I love all of the family dynamics. The two really do act like brothers and their relationships to their father and to each other are so well done.

As for the other -- I have seen shows and movies with absolutely no on-screen slash vibe... and this isn't one of them. I've heard Supernatural fandom described as Roofies -- you come in looking for a little gen about Sam and Dean's childhoods and next thing you know you're in the back room doing unspeakable acts.