Also, a good debugger. Perl's debugger is still far, far better than Python's or Ruby's.
Is it?
I generally use a graphical debugger in Eclipse. I have used Python and Perl, and can't see too much difference between them. Whats better about the Perl one?
...except for performance. The GIL is Python's achilles heel; if you throw threads at the problem Python gets slower while Perl actually uses all your cores. C.f. http://yaketyhack.blogspot.com/2010/07/threading-perl-vs-pyt...
BTW, I love Python.