Object Oriented Perl is excellent. (I do have it. :) Expect a Slashdot review very soon, as I have been writing it the past few days. (E-mail Hemos and ask him to run more
chromatic book reviews.)
Anything about Perl that comes from Manning Press is on my Must Read list now, after Elements of Programming with Perl.
I don't know how to answer the poll question, though. Does Programming Web Graphics with Perl and GNU Software count? Programming the Perl DBI certainly does, but what about Mastering Algorithms with Perl or even Practical Internet Groupware? I'm over 8 anyway. Good thing this isn't a "How many O'Reilly books did you purchase or obtain in the past year?" question.