Here's one for "Free Space on Local Hard Drives"
select distinct SMS_R_System.Name, SMS_R_System.LastLogonUserName, SMS_G_System_LOGICAL_DISK.DeviceID, SMS_G_System_LOGICAL_DISK.FileSystem, SMS_G_System_LOGICAL_DISK.Size, SMS_G_System_LOGICAL_DISK.FreeSpace from SMS_R_System inner join SMS_G_System_LOGICAL_DISK on SMS_G_System_LOGICAL_DISK.ResourceID = SMS_R_System.ResourceId where SMS_G_System_LOGICAL_DISK.FileSystem != "CDFS" and SMS_G_System_LOGICAL_DISK.DeviceID < "H:" and SMS_G_System_LOGICAL_DISK.DeviceID >= "C:" order by SMS_R_System.Name
"Install Date and Last Boot Time" (Boot Time can be skewed depending on update cycle of clients to site DB):
select SMS_R_System.NetbiosName, SMS_R_System.LastLogonUserName, SMS_G_System_OPERATING_SYSTEM.Name, SMS_G_System_OPERATING_SYSTEM.LastBootUpTime, SMS_G_System_OPERATING_SYSTEM.InstallDate from SMS_R_System inner join SMS_G_System_OPERATING_SYSTEM on SMS_G_System_OPERATING_SYSTEM.ResourceID = SMS_R_System.ResourceId order by SMS_R_System.NetbiosName
"Windows 2000 Workstations by Service Pack"
select SMS_R_System.Name, SMS_R_System.IPAddresses, SMS_G_System_OPERATING_SYSTEM.CSDVersion, SMS_R_System.OperatingSystemNameandVersion, SMS_R_System.LastLogonUserName, SMS_G_System_OPERATING_SYSTEM.Version from SMS_R_System inner join SMS_G_System_OPERATING_SYSTEM on SMS_G_System_OPERATING_SYSTEM.ResourceID = SMS_R_System.ResourceId where SMS_R_System.OperatingSystemNameandVersion like "Microsoft Windows NT Workstation 5.0" order by SMS_G_System_OPERATING_SYSTEM.CSDVersion
As you can tell, these can be modified pretty easily to suit your needs (like changing the last one to look for NT4 workstations, or look for servers rather than workstation, etc). I have some others, and will post them or send them out to you in a bit. Also, do you have the SMS Resource Kit? That has some pretty nifty utilities in it.