gamerprinter
Mapper/Publisher
While historically I prefer hard cover books, lately I've been purchasing all my RPG materials as PDF only. I run a digital print shop, so it's nothing to send specific pages from a PDF to my B/W laser printer so I can have physical copies of specific information at the table. Since I even stat up any possible encounters from a random encounter chart (if I use one for a specific scenario), there should be no missing information of the prepared evening's session. Of the books we have printed copies, they lie on a shelf near the GM's chair, so if we really need books, there they are. The players like using the books in updating their PCs, hunting for new feats, spells, etc.