Windows Server 2008 Build 6003 ((link)) ★ Recommended

: Enhanced auditing and the introduction of Read-Only Domain Controllers (RODCs) for branch offices.

The official reason from Microsoft:

Build 6003, emerging through the application of Service Pack 2 and subsequent cumulative updates, represented the maturation of this architecture. It solidified the "Secure by Default" philosophy, introducing features like Windows Firewall with Advanced Security and Network Access Protection (NAP). By the time systems were running the 6003 build revision, the operating system had shed its early stability concerns, becoming a robust platform for enterprise workloads. It offered native 64-bit support that allowed organizations to transition away from the memory limitations of 32-bit computing, a necessity for the rapidly expanding databases of the late 2000s. windows server 2008 build 6003