Also forgot to say. If you have an vm-image of a machine you can just run it on the VM Player (meaning you dont need to buy VM Ware) and thats what I do. Our uni has given us machine images on a disk that have different OS'es with different development environments installed.
That gives us a sandbox environment with no security confilcts to work in. THey also have these images avaiable on the uni network. And its great. You can literaly work in another OS on the same machine. Minimise it and go back to the host OS or maximise the VM Player and you wouldnt know the difference, bar the small toolbar at the top to get you back.
And with PC's these days their really isnt the problem with memory and other resources their was about 5 years ago. Its great for testing and if you really have too much time on your hands. You could install VM-Ware on linux then you can use windows as normal, but when it messes up simly delete the machine image and use a backup.
Its like an instant restore :)