The idea of the PDC & BDC has gone away in Windows 2000. In terms of authentication options, a Windows 2000 server will either be a stand-alone server (i.e. a member server in NT 4.0), or it will be a Domain Controller running Active Directory. If this is the only server in your environment, then you can simply create local user accounts on the Windows 2000 stand-alone server that your users can authenticate against. If you have a multiple-server environment, this becomes a serious pain -- and you should really re-think your "No Active Directory" decision.
DNS and DHCP do not depend on Active Directory to function, though if they are both running together you can do some really neat stuff to integrate them. Either service will run fine on a stand-alone Windows 2000 server.
This was first published in August 2002