What if I move my desktop inside a virtual machine?

This is a question many of you already started to ask since a while.

What if I take my everyday desktop (workstation or laptop is indifferent) and move it on a virtual machine?

How much this will cost?
Today I can have a virtualization solution at no cost thanks to the just born VMware Player. Or, if I need more, can invest a small amount of money for a complete, brand new Workstation 5.5.

What I gain?
Give me a removable USB 2.0 hard drive (USB keys are still too small for an ordinary workstation space usage), let me move my VM inside it, and fundamentally I’ll have my portable desktop everywhere I need.

Snapshots will permit me (with VMware Player this is going to be complicated) to save my steps before installing something new (like a cumbersome Service Pack or a beta program or anything else) and having multiple branches of my desktop, to consolidate when I’m sure everything works ok.

Snapshots will also permit me to backup my data in a new fashionable way: no more file level copy on a removable backup disk, but the whole VM copy just on the physical machine itself.
As many backup as I want, if enough space. As often as I want (since Workstation 5.5 snapshots can be taken on the background and launched via command line interface, scripting the whole process).
If something goes wrong 1 minute and I’m back. Faster than restoring a Ghost clone.

The hyper-flexible networking features of Workstation could provide me a sandbox environment for host OS: I’ll just unload TCP/IP from my physical network card and just let my desktop VM going on the Net.
Or the opposite…: why don’t I use the host OS below to surf in Internet mantaining safe my desktop virtual environment? When I download something useful from a site I’ll just drag & drop it inside the VM and I’ll be happy.
In this second case I could even run my personal firewall and my antivirus just outside the VM, to avoid unfair I/O performances degradation.

The VMware virtual disks manipulation tools will permit me to enlarge my desktop virtual disk in seconds avoiding additional costs for 3rd parties disk management applications.

The native screenshots and movies capture feature will give me a way to document my work at no additional cost (even if there are a lot of good open source solutions to achieve this in any way).

What I lose?
Surely I’ll lose some performances. Virtualization in desktop products isn’t as fast as in datacenter products. I’m going to forget around 15% or more of my speed, for sure (but this is going to change as soon as AMD and Intel CPUs with virtualization extensions will wide spread).

Then I lose support for some complex graphical applications and last generation games: VMware actually just support Direct3D experimentally (I could choose to install this kind of things in the host OS anyway).

Eventually I’ll lose some money, since adopting this solution is possible only if I have enough RAM inside my physical machine. And considering today’s applications requirements this means at least 1-1,5GB.

And finally I will probably lose sleep, trying to configure the perfect environment…