Apologies if I seemed flippant -- things are changing so quickly nowawdays that apart from a few core texts on algorithms and programming languages, I've pretty much stopped expanding my library. It seems to be stackexchange and blog posts across the board now.
I suspect I'll pay for this choice sooner or later...
I did buy a copy of The C Programming Language a couple of years back though, but that's just because I feel like it's just one of those books you must have.
For fiction and any other type of linear reading material though, e-readers have been a godsend.
You'd be amazed how quickly you can find something in a book (or in a few cases for me, a blueprint) when you can just hit F3 or ctrl-f and search for it.
However, I often find myself in situations where I don't know precisely the term to search for and am simply browsing to see if there is some information applicable to the problem I'm attempting to solve. That's where the ability to flip rapidly back and forth shines.
1) the current Apple trend to get rid of all PDFs has made my Mac time a pain given I cannot get good print outs of documentation or use it on something other than an iPad.
I can relate with the sentiment on paper books though. It's quite great being able to quickly flip back and forth to several places, or place notes throughout. I've had luck with the highlighting feature on my Kindle, which gives a decent interface for going back and looking at all the things I've highlighted; I've developed the habit of highlighting all the important parts in a book and going back and re-reading just the highlighted bits, which has helped tremendously. Unfortunately, highlighting across pages is rather aggravating.