As you move on from simple system-administration related tasks, you'll find that there is at least one area where Perl does not, alas, excel at - building GUIs

Now of course I'm only talking for myself here, other people will probably disagree, but I've seen very few mature, widely used and popular GUI based apps in Perl. I've tried the Perl GTK and QT bindings (too complex, under-documented) and Perl/Tk (simple but plain ugly). After those attempts, I began to understand why I could find few succesful GUI projects in Perl...

So if you're interested in trying your hand at GUI building, what should you use? Well, having never tried other languages myself I cannot recommended anything from personal experience, but I've heard Java and Python both mentioned as good GUI languages.