From Pat Rice:
One of our wenchlings asked which is hardest for us to write, character or plot.
For me, I’d have to say plot is by far the hardest. My head is inhabited with characters. They're quite likely to be full blown personalities who start arguing and bashing each other over the head before I have a chance to put word to paper. Usually, they come with some situation, so I have some inkling what they're arguing about. From there, it's pull teeth time.
At the beginning, I was a total "into the mist" writer. I just let the characters play around until I had some idea where the story started, and off I went, as eager to see how it turned out as any reader. This is the fun way of writing. Beware, it is not always reliable unless you’re a natural storyteller who automatically builds in all the necessary elements without much thought.
As I learned more about my craft, life got difficult--- What, I'm supposed to include a "black moment" at the end? Literature taught me about "climaxes," but "black moments"? I can't just blow someone up? And what’s with this Vogler stuff—I’m supposed to have a crisis in the middle, too? Ack!
I hid my head in the sand for as long as I could, but when I left my left-brained accounting job and started writing full time, with two deadlines a year, my focus went totally bonkers. I ended up wasting way too much time ripping out scenes and chapters and trying to get rid of sagging middles because my characters were just cruising on a joy ride with no purpose in sight. After I flushed a few hundred thousand words down the drain this way, I realized I needed to get my act together and instead of letting my characters direct the story, I needed to pay attention to plot or I’d be writing three books for the price of two.
So grudgingly, I attempted to plot an entire book before committing myself to paper. Or committing myself to a madhouse, whichever. And I learned if I did it by brainstorming with friends, it wasn't too bad at all. I had a good time, I came away with some semblance of story, and if I sat my rear in the chair and typed notes to myself for a while, I might even come up with GMC before I dived in. I still can't say that I actually "plot." I might say in my rough outline, "the heroine's place of employment burns up, and she realizes she can no longer live from day-to-day but must have a plan to survive the rest of her life." That would be a quarter turning point, maybe, which theoretically, ought to lead to some big deal in the middle, which teaches her a lesson she should never forget and that she needs to apply to her life. So I might know what the characters need to learn at essential points along the way, but I can never really predict how they get there. 
The above burned "place of employment" could turn out to be a circus caught in an avalanche by the time I reach that point. So I'm still writing to amuse the reader in me. <G>
But even with that rough draft of a plot, I chronically run into problems and have to scream for the aid of my brainstorming partners. I’ll whine about lack of conflict or wimpy goals and we’ll shoot endless emails back and forth, often hilarious, seldom to the point, but eventually the flood of typing brings my straying head back into focus, and voila! A germ of an idea happens.
And on days when my partners in crime aren’t available, I’ll sit there typing to myself, calling my characters three kinds of idiot and hashing over the problem at hand until I start asking what if… Ah, the notorious what if. Without it, where would novels be?
I know most romance readers prefer character-driven stories, but the degree of plot after that becomes nebulous. Do you prefer the stories that are heavily emotional and romantic, all about the relationship? Or do you like ones that have fast-paced action? Or something in between? Tell!