I went ahead and counted both my copies of Programming Perl, even though the old edition just serves as part of the 'wall o' books' bookend.
How many O'Reilly books would be a really terrifying question...There was a day last month when I went on a binge and bought 12 (had to celebrate getting a new job :).
I've just spent 8 hours on a plane reading 'Programming the Perl DBI'.
(Calgary airport bookshop had nothing of interest and I ALWAYS carry a
good Perl book for contingency).
An excellent book if you want to get your scripts to really annoy your DBA...
One. You can't browse a CD in the bathroom, on a plane
about to take off, etc. Yes, you can throw the CD in a
laptop, but a book is still more portable (and the flight
attendant won't yell at you for opening a book) :)
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.
In my occasional uncharitable moods, I wonder if, instead
of answering newbie questions, we should instead send them off
to read a recommended Perl book, and only when they pass a quiz
on basic Perl questions can they ask new ones. Then I take
a deep breath, plaster a smile over my face, and take a walk around
the building, and the feeling goes away.