I'm trying to figure out the best way to go under the current scenario: I have a Windows 2003 server on an HP ML 350 G3 (x86 hardware) and a Windows 2000 server on an HP ML 350 G2. I bought a Dell T710 (64 bit hardware) and plan on installing a virtual hypervisor on it and transferring the other two systems to it. Then I plan on putting a hypervisor on the ML 350 and making it available for backup purposes in case something happens to the Dell. Does this make sense? If I use ESXi 3.x on the old HP and ESXi 4 on the new Dell will I be able to copy virtual systems from one to the other, in case one goes down? Any advice anyone can provide would be appreciated. I'm not wedded to ESXi, so if you think another hypervisor is better please let me know. Thanks.