Doxa Digital Press is offering 27 books for $27. This collection contains books worthy of your digital library. You will find that you may have many, if not most, of these books already on your shelves. However, I find it most convenient to travel with books and commentaries on my laptop than to have them in book bags slung over my shoulder (if you know what I mean). Also, when writing, it is much easier quoting from digital text with cutting and pasting, than it is the old fashion way of transcribing text from the book.
If you have not started a digital library, now is a good time to do it. With a small investment of 27 bucks, you can have 27 good books. I have already added them to my digital library. Take advantage of this good deal!