My first book was written on my first computer. This is not a coincidence. Without modern writing tools and the ability to freely move paragraphs around and make corrections I probably wouldn’t be a writer. I need that freedom to change my mind.
In fact, freedom is generally important to me in writing. My first book was written on a generation one MacIntosh which I could easily pick up and move around the apartment to suit my current whim. Much of it was written with my feet up on the couch, the keyboard in my lap, and the computer off to my right on the coffee table. Terrible ergonomics, but ideal for my thinking process.
Now I do all my writing on a laptop and I have for as long as I’ve been able to afford one. This means I can write on the porch, at the coffee shop, in bed, sitting in the corner under a stairwell at one of my wife’s physics conferences, even tucked away behind a display at the Air and Space Museum in Washington D.C. and I’ve written happily in all those places.
2013 update: In reading this again now, I realize it’s probably worth noting that the desire for freedom in my writing space extends to the idea of societal expectations of work space. Put me at a desk and it becomes very difficult for me to write. I think that’s because my sub-conscious interprets desk as day job space. Likewise I find I work better on a chaise or easy chair with my feet up and lots of open visual space around me—ideally with lots of windows and an outdoor view. I really really don’t like feeling constrained.
On the other hand, I know people who draft long hand with a pen, on an actual typewriter, using voice recognition software, or dictating into a tape recorder while walking in the mountains. Everyone does it differently and we all have our reasons. The only thing that really matters is that the writing actually gets done.