The computer's serial number can be very useful. Among other things, many manufactuers' support sites keep record of their machine's serial numbers to serve the right drivers for downloads.
CMD> wmic bios get serialnumber
Wmic is the command line executable for performing simple WMI queries. BIOS is wmic's shorthand for Win32_bios. The PowerShell equivalent would be
PSH> (Get-WmiObject win32_bios).SerialNumber
On the production machines I work with, some do not have PowerShell installed. This being a production environment, installing PowerShell is not an option, so the wmic alternative is welcome.