I always have a light read and a heavy read to chose from depending on energy level.
Freakonomics, (the easy book) A very funny book.
Genome The Autobiography of a Species in 23 Chapters, by Matt Ridley, (the heavy book). It's a modern update of the "Selfish gene" but more in detail. It's good to read if you're sceptical on the theory of evolution. It explains things like, why a mammal mother always will love all her children equally as much. It's true just as much for lions as for humans. And why males consider being unfaithful 5/8 of the time while is only 1/8 of the time for females. It's not philosophy in any way. Just pure science.
I also read "colloquial Hungarian" at least 30 minutes a day, because I'm a good husband I want to learn my wife's native language.