I think it depends mainly on the stakeholders. If we're talking about physical machines, I suggest location/hardware based naming. For virtual machines, I'd choose function/role based naming. Though, this depends on type and size of engineering staff that needs to work with it. For end users, I'd add service based names, possibly as cnames. And I'd plan to change the naming scheme as the requirements change. Has anyone a naming scheme that lasted more than ten years?