"The fact that only hardcovers are included here suggests that they're using the numbers they need for a more sensational headline."
I agree. Hardcover sales and paperback sales are apples and oranges. For successful books in almost any genre for almost any audience, hardcover sales are concentrated, but quick. The paperback format is where a book has its legs, and the backlist is where a publisher has its foundation.
I bought a Nook so clearly I'm reading ebooks. At the same time, I have continued to purchase (way too many) actual books. Until ebook prices drop there are many books I will continue to buy in print. I frequently visit my local used bookstore and can get many books there for $3, $4, $5 (I also buy used books online) while the ebook is still $10.
The reason I bought my Nook is that when I'm at school, at work, etc I often have time to read but it is a pain to carry around more than 1 book (I like to read more than 1 at a time) and this makes it much easier.
Anyway, I agree on wanting those two bits of information (especially about paperbacks). I think we are still a ways away from ebooks over taking print books.