Apparently, if there's one thing that can get me blogging up a storm it's Hyper-V. I just can't get enough! The word of the day is "snapshots". Learn it, love it, and dance with joy.
I currently have two different main machines I've been prodding over the last two days. One is my development machine that I previously mentioned, and the other is a test machine where I'm testing install on workgroup, a domain, with different settings, etc. and storing states that I want to poke at more later - all by using snapshots. Without them, this work would have taken at least twice as long, either because Virtual Server's undo disks suffered performance-wise or I would be reimaging machines to much cleaner states than need be.
How can it get any better, you ask? Why, how about with a simple scriptably WMI interface that already has a great library of tools in a Codeplex project! Powershell plus Hyper-V makes the virtual world go 'round. If you do any manual Hyper-V management, check it out.