There are a few questions that I've found on ServerFault that hint around this topic, and while it may be somewhat opinion-based, I think it can fall into that "good subjective" category based on the below:
Constructive subjective questions:
* tend to have long, not short, answers * have a constructive, fair, and impartial tone * invite sharing experiences over opinions * insist that opinion be backed up with facts and references * are more than just mindless social fun
So that out of the way.
I'm helping out a fellow sysadmin that is replacing an older physical server running Windows 2003 and he's looking to not only replace the hardware but "upgrade" to 2012 R2 in the process.
In our discussions about his replacement hardware, we discussed the possibility of him installing ESXi and then making the 2012 "server" a VM and migrating the old apps/files/roles from the 2003 server to the VM instead of to a non-VM install on the new hardware.
He doesn't perceive any time in the next few years the need to move anything else to a VM or create additional VMs, so in the end this will either be new hardware running a normal install or new hardware running a single VM on ESXi.
My own experience would lean towards a VM still, there isn't a truly compelling reason to do so other than possibilities that may arise to create additional VMs. But there is the additional overhead and management aspect of the hypervisor now, albeit I have experienced better management capabilities and reporting capabilities with a VM.
So with the premise of hoping this can stay in the "good subjective" category to help others in the future, what experiences/facts/references/constructive answers do you have to help support either outcome (virtualizing or not a single "server")?