When you install ConfigMgr 2007 RTM/SP1 some basic collections are created like; All Windows Server Systems, All Windows XP Systems and so on.

To be able to fully support Windows 7 systems with ConfigMgr you need to apply Service Pack 2. This Service Pack is however not creating a basic collection named All Windows 7 Systems.

You can create this collection manually. To automatically fill the collection you need to create a query based membership rule. You can use the following query:

SELECT
SMS_R_System.ResourceId,
SMS_R_System.ResourceType,
SMS_R_System.Name,
SMS_R_System.SMSUniqueIdentifier,
SMS_R_System.ResourceDomainORWorkgroup,
SMS_R_System.Client

FROM
SMS_R_System where SMS_R_System.OperatingSystemNameandVersion like "%Workstation 6.1%" or SMS_R_System.OperatingSystemNameandVersion like "%Windows 7%"

As you can see I specified two criteria; ‘Workstation 6.1’ and 'Windows 7'.

Enjoy!