I received my brand new Dell Latitude E4300 laptop today and I wanted to make sure i could boot both Windows 7 and Windows Server 2008 R2 on it. Here is how virtualization came in handy. Instead of partitioning my laptop using two partitions (one for each OS) and wasting space, i created a single partition on the C:\ drive that encompasses the entire solid state disk (120GB).
On the primary partition, i installed Windows 7 enterprise RC build (7100). Once that was installed and everything worked, I downloaded a sysprep-ed VHD of Win2k8 R2 RC (build 7100) and put the VHD on the c:\ drive. I then followed the instructions as outlined on this blog post by Aviraj (http://blogs.technet.com/aviraj/archive/2009/01/18/windows-7-boot-from-vhd-first-impression-part-2.aspx). This is utilizing a new feature of Windows 7 and Windows Server 2008 R2 called "boot-from-vhd". What this feature allows you to do is to create a VHD file on your operating system and then modify the boot entries so that you can boot into it, essentially creating a multi-boot environment on your PC. Read more about boot-from-vhd here: http://edge.technet.com/Media/Windows-7-Boot-from-VHD/
Once I booted into Win2k8 R2 enterprise, I made that a domain controller, enabled Hyper-V on it, and installed VMM. Now i have a laptop that i can use daily for my work using Windows 7 and I can always show off VMM and its latest features by booting into the VHD. It might be necessary on the Win2k8 R2 partition to enable the boot property for the hypervisor to auto-start. use this command for that: "bcdedit /set hypervisorlaunchtype auto"
This also means I am not wasting any space since the VHD file will grow as needed on my C:\ partition. If i want to take any other VMs on me to a customer site, I can always copy them to the C:\ drive and reference them when i boot inside the VHD. This works perfectly.