Most of the time, I work at the Windows 7 computer in my home office with a dual-monitor setup. A lot of non-geeks have never used a dual-monitor setup: you will just have to trust me when I tell you that, for a programmer or any other person who needs to look at a lot of information all at once, it is much more productive than a single-monitor setup. It's not a luxury—it's a necessity.
When I have to leave the home office and go into the office office, I take a Windows laptop. This is less productive, due both to the small screen size and the fact that I have only one screen. So I decided to try out a couple of apps that allow one to use an iPad as a second monitor.