I think about it often, although I'm not much of a C programmer, I understand the basics. To me, Perl is an easy-to-use front-end to C. The most common big problems I encounter when doing a C program,are:

declaring the variable type, which are not intuitive, and worrying about overflows, and casting.

buffer overflows

lack of a linked list structure type (i.e. Perl's hash )

Perl modules are much easier to use than figuring out how to incorporate a C lib into your app. Static vs. Dynamic linking, etc.

Perl handles all of these for you, at the expense of speed. So as others have said, if you need speed, or are moving alot of data, C is better. But almost anything you can write in C, can be done in Perl, and it can be written faster. So write in Perl, and if you need speed, convert it to C.