That's much like the story of my professional life as well, save that I mostly deal in smallish projects which tend to be requested in PHP, so I say "I can do that faster, better, and cheaper in Perl" and they generally say "OK", so I rarely have to actually write/modify PHP code more often than once every couple months and can stick with Perl aside from that.
As for what I do with Perl...
Web apps
Logfile analysis
Dynamic firewall rules based on what's found in those logfiles
User accounting and workstation management for an internet cafe
Web scraping
Spam header analysis
Scanning for "hidden messages" via equidistant letter spacing