I read The Gunslinger a while back, with the intention of beginning the Dark Tower series. However, after finishing the book, I decided against it. To be perfectly honest, I found Rolland to be so unlikeable, I honestly didn't care what happened to him. A man willing to let a young boy fall to his apparent death so he can pursue some personal vendetta is scum, in my opinion. I realize that much of Rolland's behavior and character was caused by conditioning from the way his father brought him up (I also think, from what I read in the book, his father was scum; who else would teach their child that petty revenge is a more worthy cause than protecting others?) The thing is I just don't believe that's a good enough excuse.
As for Stephen King, I've enjoyed a lot of his other works. I particularly like his short stories, and I have Night Shift and Skeleton Crew. I also own copies of several of his longer works, but I haven't gotten around to reading them yet, save for The Running Man (which, rest assured, is nothing like the cheesy Schwarzenegger movie.)
Similar to King, I've also read a couple of Dean Koontz's works; Darkfall and Tick-Tock. The former I found fairly interesting, particularly with its take on voodoo. The latter wasn't so great; the supporting character was this weird woman with one of those deranged zen-ish personalities; you know the type, the ones that don't seem to be living in reality or seem to believe that the world works however they think it should work.