Originally Posted by Warmark 
All things being equal I like to have a box with a nice manual that doesn't need to be printed out.
What I do is get the PDF manual and put it on a cloud storage site like dropbox or box.net and then pull it up on my tablet. You can pretty much do this on any tablet, iPad, Android, Touchpad etc. In a pinch you could probably do it on a phone as well but it wouldn't be as easy to read.
Anyway, this avoids having to print the manual or alt tab out of the game to pull it up.
These days I prefer digital unless it's a collector's edition.