Just a few remarks:

perldb

Never used it inside emacs, (and hardly outside it), how well integrated is it with emacs? Do you have the ability to jump from a debug line to the source file?

flymake-mode

I prefer flycheck to flymake, but in either case, I have major issues with these, since my setup (everything is in local::lib), gives me "module not found" errors. I've tested several solutions, but haven't found one that 100% works.

Yasnippet

Not my style of programming, but a good recommendation for those who use it

Auto Complete

Excellent package, very robust. I know some also like company-mode, which can be used to force a code-style across the company (hence the name), which is a good counter argument to those that claim perl is unsuitable for large companies/projects.

ECB = Emacs Code Browser

Is this really beneficiary for perl programming? There is also the perl-critic library (available from the Perl-Critic page. A search for emacs yields a ton of results. As for the vision, I just don't thing perl needs an IDE. These, and other, tools definitely help. Utilising Org-Mode and Babel for project management, documentation etc. is a very strong tool (Org-mode is emacs killer app), but generally a full-blown IDE is just overkill for a language like perl.