I've been using a lot of virtual machines recently for various projects. My current favourite virtualisation system software is Sun's VirtualBox. It's flexible, it's easy to use, it's fast, and it's free. I've few complaints there.
However, if you ever wondered whether virtual machines would save you a bunch of time, the answer has to be yes - but a heavily qualified yes.
As the hardware makers enthusiastically tell you, virtualise and you won't have to manage lots of pieces of hardware. Instead, you'll be managing many fewer -- but, because of redundancy, far more complex -- pieces of hardware. And you may well save energy in the process, allowing you to slap a green label on the system.
What they will also tell you - but only if you ask - is that you still have to manage the virtual machines, their licences, their updates, their security, their user profiles, you name it. And because it's so easy to create new VMs, it's also highly likely that you'll have more VMs than you ever had physical ones.
And most of IT infrastructure management time is spent managing software: it's been an underlying if little-remarked trend over the last 20 years to make as much as possible manageable in software. It means the short-sleeved brigade don’t have to spend as much time crawling under desks. But you will spend as much time -- maybe more, since you now also have to manage the virtualisation system software -- in front of that management console.
This is hardly a deep insight, I'll grant you. But while virtualisation software vendors talk blithely about data centre orchestration, if you're a small or medium-sized business with scant IT resource to throw around, don't imagine that the savings from virtualising servers and desktops will be gained from spending less time managing software.
Data centre orchestration is nice if you've got a data centre and deep pockets for spare hardware resources. If you haven't, be prepared to spend more time at that PC.