I use it for ETL processing as well (*wink,wink*). Basically it's batch file processing, N number of files come into a system, we processes them performing any filtering/transformations/etc, and then load the resulting record set into a database. I work constantly in *nix land, so perl also comes out in my bag of command line tricks, which prior to Perl, was heavily awk and sed.

I've used Perl in the past to manage web applications, CGI and plain ol' dynamic web sites. I use it in maintenance mode now, since I run an installation of Bugzilla at our office.