To Plot or Not to Plot?

I have been giving plotting and outlines a lot of thought over the past few days. Is it better, I wonder, to spend time at the beginning of a project plotting out the storyline, writing down everything you can about your characters and getting to know them inside and out? Or is it best to take a more organic approach and let an idea sweep you away, counting on your imagination and the characters themselves to guide you?

I have read a lot of books about writing over the past year or so, and most of them say that it's up to you as a writer to figure out what works best. In the end though, they pretty much all say that outlining and getting to know your characters is the best way to write a successful novel. Of course, the only book I've ever read by those people are the books on writing.

Last night, I started reading part 2 of Stephen King's book "On Writing". The first part was mostly a memoir, a telling of the journey he took from boy to man, and how it affected his writing. The second part is more about the writing itself. He very clearly advocates that the best stories are written organically. He says he begins with a situation. (e.g. A popular writer wakes to find himself injured and being cared for by a crazed fan.) The characters begin as flat ideas, and as he writes, they tell their own story, fleshing out into real people. He often has an idea where he thinks the story is headed, but most often, it goes in a completely different direction altogether.

I can see both ways being good, but outlining and plotting the story before you write seems to be the safest, yet least creative way. Once a story is all outlined and settled, it is difficult to expand and let your imagination guide you as you write. If I wrote a complete outline and character sketch, almost anyone could write my novel for me. However, trusting a situation and a small idea to simply begin to develop into an entire 80,000 word book seems extremely scary. What if the characters don't magically begin to speak to me? What if my words sit flat on the screen with nothing important to say? What if the story rambles and no plot ever really develops? It really scares me. Sure, it works for Stephen King, but come on! He's like a God among writers. Sure, he's not the most literary of writers, but he can pull you in and scare you more than any writer I've ever read. And he's written over 35 books, most of which, if not all, were bestsellers.
(Not to mention the movies!)

I am no Stephen King. How do I know whether I possess the ability to write in that organic, let it come to you kind of way? Truly, there is only one real way to find out. I have already just written a short novella that was very detailed and plotted before I began. I strayed from it and changed the plot a little bit, but for the most part, I followed my original outline. Now, as I start my next project, it seems only right that I give Mr. King's method a try.