I only own 2.
The Llama (Learning Perl) - Because it's good
Perl, CGI, and Javascript Complete from Sybex - Because it was cheap and has a pretty good index.
I also have Perl in a Nutshell (The Camel Head? from O'Reilly and which I need to buy) and MySQL by Paul DuBois (which has a chapter on the Perl DBI API so it kind of counts) currently checked out from the library.
The wish list could go on for pages though. (-:

sm3g
perl -e 's;;uoli;;$a=length;y;g-w;e-u;;;$a--;s;j;$a;;print"$_\n";'