In addition to the excellent answers above, another factor that I can see is that dead-tree books IMHO relate better in feeling to their contents (at least for fantasy RPG, maybe not so much for sci-fi?).

What I mean by that is that often times the fantasy worlds that people play in are inspired by the technological state of the art of about late Medieval times. You have blacksmiths and swords and candles and that kind of stuff. While chronologically before the invention of the modular printing press (in the West), it seems to me that engaging with these worlds through "old-fashioned" paper books just feels more "in game" than using an ebook reader.

(Then again, your mileage may vary: people use their cell phones instead of dice and for calculating, too...)

What are the benefits of owning a physical book?
How do you perform a right-click-drag operation on Mac hardware?  I know you can right click, but there does not seem to be a right click drag gesture.  In my specific case I am using a MacBook Pro, and I am in a Windows environment.

The question is more than just theoretical. I ask because there is functionality that uses this gesture, at least in the Windows world.  For example, right now I'm trying to do a copy and rename in the TortoiseSVN repository browser.  I think there are things you can do with a right drag in graphical editors like Photoshop as well.  In windows you get a context menu when you right drag files.  For those familiar with the software, I know I can do it in other ways; I'm not looking for workarounds to specific problems.

I have tried this suggestion on the macrumors forums by Darth.Titan, but either have not been able to get it to work or do not understand what they are talking about: http://forums.macrumors.com/showthread.php?t=678836
