Can anyone point me at some good resources on Windows hardening? From 2003 upwards.
Baseline Server Hardening (aka, start here): http://technet.microsoft.com/en-us/library/cc526440.aspx
Intro to Hardening Server 2000: http://technet.microsoft.com/en-us/library/dd277465.aspx
Infrastructure Threat Modeling Guide: http://technet.microsoft.com/en-us/library/dd941826.aspx
Security Compliance Manager: http://technet.microsoft.com/en-us/library/cc514539.aspx
The United States National Institute of Standards and Technology has published configurations for Windows 7 as the United States Government Configuration Baseline, and for XP/Vista as the Federal Desktop Core Configuration.
On the flip side of hardening guides and standards documents, you have the posture assessment angle. These audits can help you either determine how far off standard you are, or how closely you are actually following what you've decided to implement. The two that I have used, and enjoyed are:
MBSA is an installed application that will audit the security of a Windows system, against the Microsoft recommendations, and produce an excellent report.
The Nessus audit files are included as part of a vulnerability scan and will test against the CIS benchmark.
Both tools produce great reports and can really help with your standards development and/or compliance.