In my modules (both on CPAN and private ones) I always die with a Carp::confess.

I don't like croak() because it could lead to errors that are hard to find, especially when the module that uses it is buggy.

The output of confess() contains all the information that I need to find the bugs, and it allows me as a user to judge if a bug is in the calling code or in the code of a module.