I first encountered with this wonderful virtualization product from Microsoft sometime back when we had to setup 20 computers with identical software installations for a training purpose. The software packages we required were really huge taking up hours to install (SQL Server 2005 and Visual Studio Team System 2005). Virtual PC helped us here. All we had to do was to setup one Virtual PC image with all of them and it was just the matter of copying these files into the computers and installing only the VPC software on them.
Now that I have a new laptop with Windows Vista, I didn’t want to install all my development tools on it to make it slower and problematic. Solution? Virtual PC! The new version 2007, which is totally free, now supports Vista as both host and guest. So I have a Windows XP Virtual PC with old favorites like VB6, and another VPC with Windows 2003 and VS 2003 and VS 2005. Another one is in making with Vista and .NET 3.0.
Virtual PC also helps me in trying out any software without disturbing my original system. And whenever I get new software that is not working in Vista, I can use them in XP or 2003. Now I am a complete Virtual PC enthusiast!