Community Tip - Learn all about the Community Ranking System, a fun gamification element of the PTC Community. X
Another option is to use the "setx" command which I believe used to come with the Windows Resource Kit but seems to be part of Windows 7 now. This is similar to the "set" command but stores the value as an environment variable that can be used immediately outside of the comman window where it was created.
I use this all the time in batch files or on the command line.