Well, I guess I'll better not take that bet 
I installed vCenter Server on Windows 2012 with most features, i.e. the ones mentioned plus Update Manager, Dump Collector, ... and the Task Manager shows a usage of ~4GB with 2 ESXi connected hosts, but no VMs running. In addition to this, the system doesn't have A/V installed yet, so I guess a little bit more memory wouldn't be that bad.
André