Are you an outliner or a pantser?

I was explaining to one of my memoir classes the other day about fiction writers being either outliners or pantsers. Outliners have thorough outlines before they ever hit a key on the keyboard; pantsers write by the seat of their pants. I have heard some outliners talk about elaborate charts with post-its so they can move incidents about, detailed lists of physical and emotional traits of characters, a solid knowledge of what will happen in each scene. The trick seems to be to write in terms of scenes, not chapters. That I can understand because I get carried away writing sometimes and forgt to break it up into chapters! But the advantages of this method are clear--the author knows the novel backward and forward before even beginning to write.
It's not that I begin without any outline--I have some rough notes on where the project is going, a general idea of who the victim or victims are, and a vague notion of the killer--sometimes I'm half way through a novel before I decide which of the possible suspects did the evil deed. But what I like about pantsing is that new incidents, scenes and complications occur to me as I write. One thought leads to another--if that characters said that, then maybe this could happen . . . and so it goes. Sometimes it's like I'm not writing it myself but someone is dictating. I've heard more than one successful authors say, "Listen to your characters and they will tell you the story." The biggest proponent of that theory was Elmer Kelton, and he had great success with his methods--albeit backed up by extensive historical research.
When I told my class I was a pantser, a good friend remarked that she was surprised because I tend to be organized, sometimes too much so, about everything from cooking and entertaining to planning my day's schedule.
But I got to thinking about the difference. Melinda, TCU Press production manager, and I used to talk endlessly about right-brain and left-brain. She knows she is left-brained--logical, thinks sequentially, rational, analytical, objective, looks at parts and can put them together. Thus she is wonderful about figuring out computer problems, grasping the overall business picture of an organization, figuring out what the structure of a problem is. She thinks of details that I used to flit right by.
On the other hand, even as director of the press, I tended to act on instinct. Organized, yes--my desk was always clear at the end of the day, queries and phone calls and emails answered, whatever came in taken care of. But throughout my life I've done everything from buying a house to buying a car impulsively. And I acted on impulse or instinct at  the press--a sense of what would sell and what wouldn't, an instinct about what kind of event would work, a subjective sense about things. I used to tell my former boss that God didn't mean me to read spreadsheets, and one day he countered with "Oh yes she did!" Sure, I can read them and grasp what they tell me, but I still followed my instinct. Did I make mistakes? You bet, but I also had some pretty good instincts that brought us some fine books. Melinda never trusted me to proofread--"You're right-brained," she'd say. "You don't have the mind for details." Actually I'm not that bad at proofreading.
Does being a pantser stand me in good stead as an author? Hard to tell at this point--so many of the novels I've written in the past were history, so the "plot" was laid out for me, as it were. But I've written two mysteries I like (and a few others I'm not sure about) and I found that instinct did lead me, telling me where we'll go next. Only publication--coming soon for one--and reader reaction will tell if my method is successful.
So what about you? Right-brained or left? Outliner or pantser. It doesn't just apply to writing folks--it has to do with all life.