Please don't use mod_perl unless you know that you have a very good reason to do so, versus making use of more modern solutions.
Mod_perl was a great technology in its day, from the late 1990s through the mid 2000s (when, you'll notice, the last review here was added). Apache::Registry all by itself provided a great boost to Perl-based web solutions. But that was a long time ago.
Since then, the Perl community has effectively moved away from mod_perl in favor of Plack, which itself works great with the Apache web server (among others). Please closely examine Plack, especially for new projects, but also when considering ways to quickly adapt and modernize old CGI-based codebases.
HTML::FormFu, I'm leaving you.
Was turned onto this module by the helpful souls in #Catalyst on irc.perl.org. Having my web applications use this at the model layer is so much cleaner and easier to maintain than having controllers roll their own email by one ad-hoc method or another. Well done!
Learned about this via Perl Best Practices and I've been using it reflexively since then. Small, simple, does what it says.
I have been a casual Moose user for several years by way of DBIx::Class. I finally invested a day or two into learning Moose-based programming properly, and it's absolutely changed for the better the may I write model / logic classes for my web applications.
I still have a lot to learn (which will probably always be the case, thanks to the countless acres of MooseX modules), but I can't see doing any significant object-oriented Perl programming outside of a Moose anytime soon.
This has been my favorite web application framework, and the basis of much of my creative and professional work, since the middle aughts. The community (based around the IRC channel) is large, active and helpful.
I've been happy to see the project's leadership not shy away from having the framework adopt new community standards (e.g. Moose and Plack) after they come to prominence. I can see myself confidently continuing to use Catalyst for a long time to come.