The old west is an awesome setting for horror stories, if I might be so bold. My first graphic novel is a western/horror combination, called STRANGEWAYS: MURDER MOON.
You can read the first chapter right here. Something about being out on the frontier between civilization and wilderness makes the old west a natural fit.
And if I might be so bold, I can recommend the second STRANGEWAYS book, since you can read it for the cost of precisely free.
Just head over here. There's even a weekly contest to win a copy of the first book; this week's is running until tonight at midnight.
BURROWERS sounds worth a look at least, just for trying something new and not simply treading the same old ground. But I'm so behind on my netflixing that even if I dig in, I probably won't get a chance to watch it until...uh...Christmas...
If the horror/western combination seems intriguing at all, I'd recommend RAVENOUS, which, while not strictly old west, has a historical setting and a really wicked sense of humor to boot.