OS + SQL Server Recommended

Hi to all, my question is what operation system & sql server is recommended?

Windows XP + SQL 2000 sp4
Windows XP + SQL 2005

Windows Server 2003 + SQL 2000 sp4
Windows Server 2003 + SQL 2005

Windows Server 2008 + SQL 2000 sp4
Windows Server 2008 + SQL 2005

Thanks and sorry for bad english :/:

:thumbup:

Windows Server 2003 SP1 Enterprise Edition 32bit + Microsoft SQL 2005 Enterprise Edition