Unless you have a heavy number-crunching application, or something with very tight real-time requirements, Perl will be an option (though, for sure, not the only one).

But also remember that premature optimization is a mistake. Go ahead and write that number cruncher in Perl, and profile it. Then rewrite problem areas with XS or inline C, if somebody hasn't already done that for you and uploaded it to CPAN, and profile it. Then rewrite problem areas with inline assembly!

It sounds like a lot of work until you compare it with learning a new set of languages (yes, I'm assuming familiarity with C). On the other hand, that isn't a reason not to learn other languages or environments, especially as widely used as Python and MATLAB and R and such. But I prefer doing that when I have the presence of mind to enjoy it, not when I'm under a deadline. That's what brought me to Perl, after all.