I recently (like yesterday) converted my Windows 7 BootCamp partition over to a virtual machine. There were many factors that led to this, but ultimately it boiled down to the fact that I ran out of hard disk space on my partition and there was no way for me to increase the capacity. In the past I would have to go back and uninstall a bunch of applications. However, this was getting old and it was a never ending battle. I was living on the edge (of disk space).
My solution was to virtualize my Windows 7 machine and scrap my partition. This would allow me to give more space to my Windows 7 OS whenever I want to (along with other benefits). The whole process took about 2 hours. I started the process @ Barnes & Noble and then ended up driving home with my laptop open in my passenger seat. The process finished as I was driving through Newark. :)
One of the first things I noticed was that Time Machine was backing up my entire 50 gb image every hour. It actually did this 3 times (which is now hogging up 150 gb on my Time Capsule). I ended up having to "Exclude" my vdd file from the backup process and now my backups are normal again.
I feel much more confident about having my Windows 7 machine as a virtual hard disk now. I still have a lot of learning to do in regards to cloning a base image of it so that I can install other software without affecting my MAIN image. But for now, I'm just happy to be able to "Suspend" my image and free up some resources whenever I want now... without having to "Shutdown" Windows 7. :)