I prefer a laptop over a desktop computer because my electricity tends to go out whenever anyone sneezes on the electric lines in my neighborhood. Thus, I sometimes have to drag my pajama’d carcass to the nearest library, book store or Internet cafe to get back in business. When you’re dealing with corporate professionals, you must keep your customers happy at all times. You must be ready with a Plan B when something goes wrong. Being mobile helps.
You’ll also be able to take your business with you when you travel. When my friend was in a terrible car accident, I stayed with her during her first week out of the hospital. With my laptop along, I was able to make money and help her at the same time. I once wrote an entire website for a corporate client while on vacation in Hawaii. I know, it seems a sad way to spend a vacation in such an amazing place, but the client was desperate and the money was too good to pass up. I only worked in the mornings and that single project more than paid for the vacation! I couldn’t have done that with a desktop.