As modules mature, the coupling between modules is getting just a bit tighter, which I think is a good thing. For example, CGI::Prototype (linked below) is explicitly designed to work closely with Template Toolkit (ditto) and, of course, CGI.pm and Class::Prototyped. Other examples (though not on my list) include Maypole (Class::DBI, Template) and WWW::Mechanize (LWP).

My favorites:

• Plucene is an incredibly flexible and easy way to add full text search (If it doesn't seem easy, try reading the Perl.com article on Plucene. And note that "Plucene::Plugin::Analyzer::Porter" should be read "Plucene::Plugin::Analyzer::PorterAnalyzer".) It is also pretty Perlish despite being a Java port. But the Slashdot folks, among others, have had trouble getting Plucene to scale, and the module needs retooling before it is production quality (at least that's what one of the maintainers said on the mailing list). At the moment the maintainers have their hands full with other projects, although they may be doing work I don't know about (all have commitments to other marquee modules).

• CGI::FormBuilder just passed 3.0, with a more modular and extensible design. It has saved me a lot of time processing Web forms, handling default values and validation in flexible manner and playing well with Template.

• CGI::Prototype helped me consolidate nine CGI scripts into one, along with a small number of very short classes. It was actually very easy to set up. This despite its still-sparse documenation (merlyn has said more is coming).

• Class::DBI has quickly made itself indespensible. Object inflation/deflation still seems unintuitive to some smart Perl programmers on the list, but this is a not a huge complaint, especially since it is so durn easy to subclass Class::DBI and there is a comprehensive set of callbacks.

• Template (aka Template Toolkit)