We have an eclectic mixture of scripts developed over some time. A lot are shell and Perl4, the more recent stuff is Perl5 but I really mean recent, when I started there less than six months ago it was all Perl4. I am trying to encourage use of modules but given the normal security/paranoia/big.org it is not easy to push anything outside core. It also all has to be cross platform (win/aix/linux mostly, some special stuff for mainframes but that is an accepted exception to X-platform rules).
The stuff we are mostly using outside of core are XML modules (we use J-meter to run synthetic transactions on web pages and it reports in XML) and various DBI modules.
from core we use the threading modules, IO::*, Time HiRes, Net::Ping, FindBin, File::Find and a handful more I can not recall without greping our source.
We are building a large library of our own modules, some very in house and some that I am trying to get on CPAN. Ironicaly management love open source (free as in beer) but when I proposed to put some of our modules on CPAN I hit a sort of sand trap of redirection and passive resistance. No one will say no but no one will approve it either.
So for the most part now it is writing wrappers for legacy code and working on the sexy new core system.
Drop me a /msg and we can discuss further withouth going to re^12 and filling up nodes with trivialities for others.