For all the talk of CPAN being so killer, there actually isn't much there that other languages don't also have. There may be more choice in implementation of a fairly common concept, but that's the Perl way. The "aha, I'll use Perl because this CPAN module implements exactly what I want, and nobody else does" moment rarely happens.
You can see a list of recent uploads here: http://www.cpan.org/RECENT.html
> There's tons of choice with date libraries,
Most everyone uses DateTime.
> or OO frameworks,
Nowadays choosing this one is simple: Moose
> or unit test frameworks
Test::More is pretty standard.
> For all the talk of CPAN being so killer, there actually isn't much there that other languages don't also have.
That is approximately the opposite of my experiences with the CPAN.
Overall Perl use may have declined, but good, effective, maintainable Perl use by people who're involved in the community is on the rise - and that's the group that I'm a part of, the people who write Perl as a robust, team-oriented, scalable production language rather than the PERL scripters of old (and my thoughts go out to the PHP and ruby communities who seem to have acquired a similar breed of idiot this time round the hype mill).