As far as debuggers go, I used them extensively for a number of years when I was working on multi-threaded C code, but I haven't touched them since I moved to Perl. This is probably due to the quicker turnaround time of making changes in perl (e.g. to insert a debugging print statement, or a Data::Dumper of a structure) and the fact that perl doesn't tend to have really pernicious low-level problems like C (e.g. core dumps, memory leaks, etc). Debuggers are nice when you have exausted other paths and you have time to burn. For me, it's not worth the effort to pick a good GUI for this.
As far as IDE's, I use emacs. If you pick something that is relatively generic that has syntax highlighting and some intellegent editing (e.g. vim), you won't have to learn a new environment when the next new language you are required to use comes down the pike, though Perl is a welcome relief...
bluto
