If the performance is acceptable, I'd love to do all of my daily Windows work from a VM... on a removable drive I can boot with no fuss on my desktop, laptop, or friends' computer.
If they can really isolate all the hardware this is a game changer for me. I'll just move my SSD seamlessly between various PCs at home and work. Epic win.
Don't dimiss this as a power user feature just yet. Imagine going on vacation and taking one computer for your family, not 4. Get a new computer? Don't "migrate" with current solutions, move everything with full fidelity. Keep your own personal OS for use at internet cafes. Change the form factor of your computer at will.
My development machine is Windows7. I do web and systems development in Python, PHP, etc.
All of my development is done on Ubuntu and CentOS VMs running in VirtualBox.
My actual IDE is often Eclipse (or Eclipse based) and I just make an SSH/SFTP connection to each virtualbox and the coding is treated as a "remote project" in Eclipse.
When I retire this Sony Vaio, I'm really thinking I'll get a 15" Macbook. Just for variety. There was a time when I'd never have dreamed of that. I bill a high hourly rate, I cannot be fumbling around because I'm on an unfamiler OS.
But I could switch to a Mac in 60 minutes. Downnload a JVM and VirtualBox for OSX, move over all my VM images, and I'm done. Back to work.
I chose Windows 7 because IMO it's the best OS available for me. I enjoy it. I never have reliability issues. I find I usually go 30, 40 days between restarts. It's nice I have this option: the chip and OS makers have really done a smashing job on visualization technology over the last decade.
I had a dual-boot setup like this on an external drive with Windows and Linux when I was in high school. It was pretty useful whenever I needed to use one of the school computers. Not seriously game-changing, mind you, but somewhat convenient (more pleasant and useful than portable apps).