Perl is the humble workhorse that is doing work _somewhere_ on even the most snobby person's network. Perl5 has at least a few very good years left in it. The perl program itself is quite fast, super portable and extremely stable.

There's a lot of great reasons to choose Perl for a project. There's not too many reasons to choose Ruby, Python or PHP over Perl. The most common one is a personal preference based on the feeling that Perl is "old and crufty" and these other languages are "cool". Most cite "I don't like objects in Perl" as the primary specific technical complaint. Most of these people never got very far into Perl, some did.

Perl under Lighttpd/FastCGI or Apache/mod_perl is very capable of matching or besting a similarly configured J2EE/Ruby/Python/PHP system in bang-for-your-buck performance comparison.

CPAN is simply unmatched in the history of code repositories. There are some minor issues with it. Huge time savings. No language comes close, yet.

The Catalyst framework.