Buy Microsoft Windows Server 2003 Enterprise with SP2

Microsoft Windows Server 2003 Enterprise Edition is the premier platform for business-critical applications. Windows Server 2003 Enterprise Edition builds on the standard features found in the Windows Server 2003 family by adding features designed to increase the reliability scalability, security, and manageability of enterprise applications.

This version of Windows 2003 Enterprise is direct from Microsoft, with Service Pack 2 integrated. It is also corporate, so no activation is necessary.