Virtualization Demos – Remote or Local – Mac or PC

Many of us have to demo virtualization technologies to our customers and colleagues, run classes, develop code for virtualization, or just play around. For many of these cases, a cloud based virtual environment may be fine. However, what do you do when the network connection to the cloud is flaky at best? You have to rely upon your local system to do the job for you. Some solve this problem by having a ready slide deck, others solve this problem by using a fairly high end laptop, and still others tether their laptops to their phones and other cell phone cards. Which method is best?
I have always found local access to my laptop has always been the better way to run demos, classes, and presentations for my customers, colleagues, and friends. As I write software for and books about virtualized environments I almost always need access to various virtualization systems. Where I can I use network connections as going back to the office lab is in most cases much faster than local, but when I have to run things local due to telecommunication issues a high end laptop is a requirement. But which one?