(something tells me this thread will stick around for quite some time and will break some length records)

I use Perl for my school and job duties, which is solving computational linguistics problems. That involves dealing with XML, manipulating text files, dealing with encoding issues, interacting with other programming languages (like R) and using mid-complex data structures.

I actually use Perl for everything that needs programming and where I can use Perl. I found that since I started using Perl, there are more and more tools that I wrote among those I use. Whenever I do something regularly and it can be automated, it's time for some Perl. :-) These little thingies include a script for archiving mail from OKcupid.com, a script for timed saving internet streams (good when you're not at home when there's your favorite radio show), and TK program for sorting photos that you get from your digital camera.

I also recently started writing web apps in Perl.

What I don't use Perl for is system administration. I got used to Bash and standard Unix tools long before Perl and I don't feel a need to switch (however, some Perl occurs more and more in my command pipes :-) and I have aliased grep to pcregrep )