You should be using VMWare

VMWare makes it extremely easy to replicate configurations, and to get back to a known good state.

I only recently started using VMWare, but in the few months that I've had it, it has worked flawlessly. I've found that it's useful for several common tasks:

- Testing (and re-testing as needed) software installations. You can create multiple virtual machines (one for Win2003, one for Win2KPro, one for XP, one for RHEL, etc.), and you can take snapshots at different times. For example, I have a snapshot of one Win2KPro virtual machine with SP4, IBM Directory Server 5.2, and WAS 5.1. I can do whatever I want to this virtual machine, and still get back to my original starting point. This is basically very similar to Ghost'ing a machine.

- Creating proof-of-concepts. You can run multiple virtual machines simultaneously (with enough RAM), and this has helped me create a TIM/IDI/TAM configuration that allows me to automatically provision TIM and TAM accounts, with access to backend applications, based on the contents of a file. And a really nice part is that I can always get back to my starting point if something goes wrong. And you can have multiple snapshots for a single virtual server, so you can go back to any snapshot you've taken.

- In a production environment, VMWare can definitely allow you to easily, dynamically allocate resources to different tasks. VMWare, along with z/OS and AIX LPARs, form the basis of IBM's Orchestration and Provisioning vision, and I can attest to the fact that VMWare seems to be at least as robust as a real PC, so I believe it's a valid technology to rely on.

In summary, if you aren't yet using VMWare, you should be. If not for its features alone, then you should use it to learn the technology, as it is already present in a large number of companies. Additionally, VMWare Workstation is reasonably priced at around $190 per server.