There have been a couple of minor changes to the New Virtual Machine Wizard in Virtual PC 2007 to help address usability issues that have been identified. The first change is to the operating system configuration page. I have never liked this page myself, as you select an operating system and have Virtual PC perform a number of unknown actions as a result. With Virtual PC 2007 you are now informed of what the result of your operating system selection will be:
One other minor change is that you can specify a custom virtual hard disk size if you choose to create a new virtual hard disk as part of the New Virtual Machine Wizard.