9. Reduce the data center footprint
This one goes hand in hand with the previous benefit. In addition to saving more of your company's green with a smaller energy footprint, server consolidation with virtualization will also reduce the overall footprint of your entire data center. That means far fewer servers, less networking gear, a smaller number of racks needed -- all of which translates into less data center floor space required. That can further save you money if you don't happen to own your own data center and instead make use of a co-location facility.
8. QA/lab environments
After completing a server consolidation exercise in the data center, why not donate that hardware to a QA group or build out a lab environment? Virtualization allows you to easily build out a self-contained lab or test environment, operating on its own isolated network. If you don't think this is useful or powerful, just look to VMware's own trade show, VMworld. This event creates one of the largest public virtual labs I've ever experienced, and it truly shows off what you can do with a virtual lab environment. While this is probably way more lab than you'd ever actually need in your own environment, you can see how building something like this would be cost prohibitive with purely physical servers, and in many cases, technologically improbable.
7. Faster server provisioning
As a data center administrator, imagine being able to provide your business units with near instant-on capacity when a request comes down the chain. Server virtualization enables elastic capacity to provide system provisioning and deployment at a moment's notice. You can quickly clone a gold image, master template, or existing virtual machine to get a server up and running within minutes. Remember that the next time you have to fill out purchase orders, wait for shipping and receiving, and then rack, stack, and cable a physical machine only to spend additional hours waiting for the operating system and applications to complete their installations. I've almost completely forgotten what it's like to click Next > Next > Next.
6. Reduce hardware vendor lock-in
While not always a bad thing, sometimes being tied down to one particular server vendor or even one particular server model can prove quite frustrating. But because server virtualization abstracts away the underlying hardware and replaces it with virtual hardware, data center managers and owners gain a lot more flexibility when it comes to the server equipment they can choose from. This can also be a handy negotiating tool with the hardware vendors when the time comes to renew or purchase more equipment.