Some of those may be bad books for teaching you to be a -good- Perl programmer, but the important thing is to get people interested in Perl in the first place. I started with with the Matt Wright script archive book and Teach Yourself CGI Programming with Perl 5 in a Week, neither of which are that great, but they taught me enough to get started writing / modifying basic Perl scripts.

I say keep the books - not everyone has money for new, better books. If you think the books aren't first-notch, just paste a blurb on the inside cover telling people where to go to learn more (perlfunc, perlvar, and here).