As stated above, Perl's strength's lie in its ability to be able to perform well in most realms (web, network, databases, XML) without necessarily being the absolute best tool in any particular area

The reason? To my mind it's CPAN. The culture around Perl has encouraged the building of a treasure trove of exceedingly useful modules. In most languages, if you have to deliver a solution, you need to start coding from scratch or scouring the web for libraries/modules/utilities that someone may have written already. CPAN can set you well on your way in many instances.