I never leave home without my mobile office (laptop, printer, smartphone). At Disney, and most hotels, I just set everything up on a desk and leave it there. No one has ever bothered anything other than a maid at the Grand Floridian straightened some papers that I left in mess.
Besides the necessary evils of work, it is quite useful for the trip. Others have already mentioned downloading the days pictures. It is also nice to have access to the Disney official site and informational sites like the DIS. Being the Type-A planner, I keep a spreadsheet with the park hours, activities, and reservations. I can easily change on the fly and print out a new sheet.