A short note about backing up your VMs.
One of the next (and sometimes forgotten) issues after you have virtualized your life is now how do you save it? You could keep performing backups the same way you have for years however I would recommend staggering them as if they all start at the same time you stand the risk of creating I/O contention on your SAN. Now you have an alternative method since your virtual servers now are living in essentially files or possibly a LVM style partition, depending on the technology you are using, let's take advantage of this situation.
Using methods provided by traditional solutions as in Backup Exec with the VMware agent or even looking at newer offerings such as Veeam or PHDVirtual you can achieve successful backups easier then sticking with agent per-server (virtual server in this case) methods. The new style software that specifically supports VMware or Xenserver are agent-less and are gaining features that can either equal or even exceed what physical server backups are capable of. Missing in the physical server world compared to the virtual world is the visibility at a lower level from the volume where the data or files reside you are concerned about. On one side we are dealing with platters inside of a physical disk compared to the virtual side where we can easily see a layer under the operating system's disk. Some of what is built into VMware, and to a lesser extent with other solutions, allows us to intelligently deal with this data.
Bottom line - if you are having trouble getting good reliable backups in the physical world perhaps virtualization can assist along with other cost cutting reasons.