The Dome is a huge 1,000+ page book but it reads really fast. The book had aliens but it wasn't stupid like the show, I stopped watching mid-way into season 2 and never regretted it.
Needful Things was another great book but I don't recall if I saw the movie.
Scariest book by Stephen King, for me, was Cell, it was about people having their brains scrambled by cell phones. Didn't fuck with my phone for a week >