Switching between Server Core and Desktop Experience?

At what point do you need to decide whether your brand new server is going to be a Server Core, or a full Desktop Experience version with the traditional Windows graphical interface? It would be common sense to make this decision during the operating system installation process, right? Where you choose from the DVD installer which version of the OS you are putting into place? You are exactly right, except that in previous versions of Windows Server we had the capability to switch a live server back and forth between the two modes. If you had a full graphical version of a server running and wanted to change it over to a Server Core to get some enhanced security benefits, you could run a command and do just that. And the same is true in reverse; if you were running a Server Core and couldn't figure out how to configure something from the command interface, you could run another command which would change it over into the GUI version...