To answer your initial question -- that depends on what you are trying to solve. :) You need to be more specific to get a answer with more value than that. You need to think in terms of readability, maintainabilty, correctness, robustness, etc.

Here is a constructor i like use when the situation is quick and dirty

sub new { bless {}, shift }
[download]

sub new {
    my $class = shift;
    my $self  = {
        foo => 'bar',
        baz => 'qux',
    };
    return bless $self, $class;
}
[download]

I try to use Class::MethodMaker whenever i can, i just like that module. Here is an example where i use that module to turn XML into real objects: XML::Simple + Class::MethodMaker. Hope this helps. :)

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)