Windows 2000 is more secure out of the box than Windows NT. This does not make it secure. Fortunately there are now several good resources on the net which provide security checklists for hardening and securing Windows 2000.

• Center for Internet Security Level-1 Benchmark and Scoring Tool for Windows 2000
  
• Hardening Windows 2000
  by Philip Cox. An online pdf with lots of good advice.
  
• InterSect's Windows 2000 Security Configuration Document
  
• NSA Securing Windows 2000 Security Recommendation Guides
  
• Securing Windows 2000 Network Resources Scenario Guide
  MS, 403K