SQLite is a fast and very capable stand alone database. It has transactions, views and subselects. DBD::SQLite is distributed with the entire database engine. That means there are no version incompatibilities and that you don't have to install sqlite first.
This is an excellent module. I use it for every small project that needs a database.
So long, MySQL.
Update november 2007: Took 1 star away because UTF8 issues remain unresolved.
This module does not add much to standard perl. As the POD says, it is just syntactic sugar.
Unix.pm lets you write "$foo = UNIX $bar;" instead of "open $foo, '-|', $bar". It takes 800 kB (on my system) to get this functionality.
The POD is broken in the SYNOPSIS. The author should run the POD through pod2text before making dist.
The module includes a test script, but it is not portable and does not check for errors. (The test script is the same code as the SYNOPSIS.) The author should really read Test's documentation, and learn to use ok().