The idea of the PDC & BDC has gone away in Windows 2000. n terms of authentication options, a Windows 2000 server will either be a stand-alone server (a la 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