Server Consolidation Through Virtualization

I'm really impressed with this latest version of VMWare Workstation 5.0 that I'm running on my laptop. I see that opened up a beta of VMWare Workstation 5.5, but I've not downloaded to try it yet. Then I got to thinking that it would be pretty sweet if you could do something like this at the server level. A little more looking and I found that VMWare does have a server version, actually two, VMWare Server GSX and VMWare Server ESX products. From what I can tell, GSX runs on top of a Windows or Linux network OS where the ESX is a type of OS itself and runs on the "bare metal" of the server hardware, not on top of a OS. Here at work we keep growing servers, we have at least 11 now. I'm intrigued by the fact that I could take a number of these and run them as virtual machines on one big box. VMWare even has a utility to help you convert from physical to a virtual server called VMWare P2V Assistant. VMWare Workstation has a "Snapshot" feature that lets you take a "snapshot", or picture of the state of the machine and software on it, then revert back to it at anytime. I used this yesterday on a vm I had Microsoft Windows Server 2003 & Microsoft Exchange Server 2003 to see if it would work ok with the Exchange STORE (usually very finicky). It worked perfectly! I was very impressed and the snapshot didn't take long to complete and restore, maybe 3 minutes at the most. The possibility of restoring a dead Exchange server (virus, etc) in under 5 minutes has a lot of appeal!