I use a Compaq nc8430 as my primary work laptop. I was quite disappointed to find out that the Hardware Virtualization feature of Virtual PC 2007 was disabled and "not supported" on my laptop.
I asked around and was told by someone who will remain nameless that the laptop version of the Core 2 Duo didn't have this capability. Thanks to Scott Hanselman, I now know that the capability is available on my laptop. HP decided to disable it in the BIOS by default. After I enabled it in the BIOS, Virtual PC uses it:). I am not sure how much of a difference this makes, but it sure doesn't hurt!