Vim

• Emacs

Debian

Any form of *nix environment does for me. I do the majority of my Perl coding at work on a Winbloze 7 box and Cygwin/X.

I'm surprised your list did not included:

• strict
• warnings
• Carp

For me I'd add the following:

• MIME::Lite
  or some other module that allows me to send EMail with binary attachments. I show MIME::Lite on my list because over the years that's the one I use most.
• XML::Simple which I typically use for configuration parameter storage for my more complex Perl projects.
• Subversion, CVS or other version control environment
  I call this "super save" because it means there's a version of what I'm writing someplace else. I do frequent commits to my SVN environment just so if I do something really stoopid to my workspace I can recover easily. It also means that I can work on one host, do my debugging and use svn co http://..... to pull the latest version onto another host. I notice you have git in your list, but I ain't ready to give up my investment in time to convert my subversion repositories to git just yet.
• CPAN Search to look up particulars on various CPAN related modules that I'm using.

That's all I can think of right now. Lots of scratch paper helps sometimes to help me visualize what I'm doing...