Writing on the go is not ideal, but necessary sometimes. I've read about writers who will work on their laptop as they wait--in their car--for their kids. Whatever happened to a pen and paper? I always have a pad and pen with me so that I can jot down ideas or write out a passage that comes to me. It can be added to any document later when I'm home. It's also far easier than carting around a computer. Soon enough I'll have an app on my iPad that will allow me to revise docs on the go--much easier to transport. Plus, you reduce the risk of theft. You're likely to leave the computer in the car while running errands and if your vehicle gets broken into... Anyway, something to consider.