Plot vs. Spontaneity

While reading On Writing, Stephen King challenged my process of writing, “Plot is, I think, the good writer’s last resort and the dullard’s first choice.”  Damn.  Apparently, I've been writing pedantic stories.  Doesn't bode well for a successful career.  

By nature, I am a control freak and prefer to plan everything out, albeit day trips, vacations or my novel.   Back in November 2010, when I embarked on the insane NaNoWriMo challenge, I created an outline of my entire mystery novel.  Being the first time I’d ever written anything so long, I felt safer with a plan.  As I wrote, my story deviated from the plan.  I listened to the story, letting it lead the way, but still knew what I wanted to happen in the story. 

Of course you will find many writers split on this topic.  Some contradictory advice I’ve read says writing without an outlined plot leads to bird-walk writing.  Presenting you with the task of cutting large parts of your prose because it doesn't having anything to do with the story. 

King on the other hand believes stories “pretty much make themselves.  The job of the writer is to give them a place to grow (and to transcribe them, of course.”  He puts his characters into a situation and allows them to work out the solution on their own with no input from him. 

He admits some of his novels were written based off a plot outline, but he really tries to avoid these situations as much as possible.  Rose Madder and Insomnia, products of plotting, were “stiff, trying-to-hard novels” he feels.  Personally, I really enjoyed Rose Madder.

 Stories are fossils, according to King.  They are found, not created.  The stories come to a writer through dreams or everyday observations, but they already exist.  “And none of the story’s details and incidents proceeded from plot; they were organic, each arising naturally from the initial situation, each an uncovered part of the fossil.” 

So, I’m left to mull over my writing process.  The only way I can really decide between plotting and spontaneity is to give the latter a try.  I know removing the safety net of an outlined plot will produce an eye twitch or two, but what have I got to lose? 

Do you prefer plotting or spontaneity when writing?