I wondered if someone might ask why I left out Python :-) It is also a viable option (as is a few other languages). But I see even fewer Windows Sys Admins using it. If you have a Python background and need to write scripts for the Windows environment, then you probably shouldn't look at anything else. You can accomplish pretty much the same things with Python as you can Perl on Windows. But I still prefer Perl :-)
A good follow-on question to this article is Perl or Python? (in the Windows environment) If you knew both, would one be better than another?