I can honestly say that I've never had serious thoughts of murder or torture ever, reading SK or not...
I can't say that I really have either, or at least Killing or torture outside of the defense of family and self realm. I've just found that dwelling on certain thoughts tend to lead to actions. Most people including myself Lust for Power, and anything that awakens that lust I just stay away from. Hannible Lector impressed just about everyone who read the book or watched the movie, we should not be impressed with someone that evil regardless of their intellect.
So I try to divest my mind of any evil thoughts and emotions. I don't watch too many movies that aren't uplifiting in some way, and have slowly become the same way with my reading. I tend to be a more pleasant lunatic if I stay away from certain types of thoughts. I am slowly learning to avoid all things that elicit negative thought and emotion. It's far easier to steer a wide path around them than it is to try to sort them after exposure. Stienbeck is one of my favorite authors, but I don't often read his stuff becuase it tends to be very dark as well.
BTW, the tommyknockers was a fun read, and if you like Stephen King I would reccomend it.
Dave