I received my Sony at the end of February last year and didn't start using it until early the following month (as I was reading a paper book and wanted to finish). Once I started using my Reader I haven't picked up another paper book in 11 months.
I read a book a week on my Sony versus a book a month when reading paper books (mostly because I can take my reader everywhere). I don't necessarily look at what authors/titles are available but what ebooks are available. The best thing for me was the discovery that I can borrow ebooks from the library.
Most of the old paperbacks and hardcovers I had sitting around went to the used book store and in return I got a crisp $50 bill.