I mentioned it on an episode of the podcast, but I've got to go with Supernatural.
On the surface, it's a Monster of the Week show. And sometimes, the plots are blatant rip-offs of other horrors, which is ok to do in a game once in a while. We're all fans of Sci-Fi/Fantasy and once in a while it's fun to replay some of our favorites. It eases the pressure on the GM. Don't copy everything, and not even so it's terribly obvious, but inspiration is a great way to get stories.
I think Supernatural lends itself well to gaming in a couple of ways:
It explores a ton of supernatural legends and creatures and really brings them to life. Ok, so there's a shapeshifter... but did you think about what happens to its skin when it changes form? Or how it can assume the shape of someone nearby? Nice details that could really play out well in a game.
I also think the format is how a great game of any genre should be- weekly adventures with a very broad connecting feature that let the PC's go in a lot of directions while still staying in the scope of the overall plan, but the characters have well laid out goals and motivations. Sam and Dean, especially in Season 1, do the same thing but for really different reasons, and that is shown really well. There is an overarching plot that is dealt with well too- about every other episode advances it in some way to keep it alive and in the forefront of the PC's attention.
It would be a good study for a new DM I think.