Just me, but I am more in Doug's camp - I prefer more literary choices than manual and technical style books. Yes I am a bonafide gear head and gram weenie, but absolutely my entire concern is for all of that to totally fall away once I'm out there. This never completely happens, but the ultimate goal is for the gear to just disappear in my mind just as much as on my back.
Also, though like Nick I have all the stuff at home, I am *very* far from needing (or wanting) additional "entertainment", especially of the electronic variety, on a backpacking trip. Its kind of the point of the backpacking trip to take a laxative to get that stuff out of my system and see what is left.
That said, I have been known to print out little DIY pamphlets to read. Stuff like Emerson and Thoreau are good - there is a nice thin paperback of 'Walking" and "Nature" I take sometimes. Also Dogen's (Japanese Zen Master from 11th century) Mountains and Rivers Sutra is a good one because it makes little rational sense, and will bear reading over an over again like a poem. Now that is multi-use literature! Also it is only about 10 pages or so. Anyway, it seem to work for me on a longish trip.