I think the downside to digital references, especially the internet based ones, is that distractions are plenty (like haphazardly getting sucked into that bizarre part of Youtube for an hour before coming to your senses). So I think it depends on how much you like books and if they fit into your life.
Very good points and yeah. that's along the same thoughts I was having.
There's a difference between a reference book and a tutorial book. For tutorial books, I would say no, it's probably not worth the investment, because once you've done the tutorials, you'll probably want to move on to other ideas. For reference books, I personally like reference books. Unfortunately there don't seem to be that many really good ones around. I have used the MEL Scripting for Maya Animators book as a reference a number of times. Often it is faster to just do a search, but I kind of wish that there was a nicely cross-indexed and formatted reference book for Maya nodes and attributes. Could be very useful.
Indeed. Especially in the areas of MEL scripting. But your right, most of the books I am thinking of are more tutorial based books. Still, I may just get them to have'em cause, you never know if you'll forget how to do something and it doesn't harm anything but your wallet. lol
Thanks guys! Appreciate the advice. 
~CJK~