
Nausea is the story of Antoine Roquentin, a French writer who is horrified at his own existence. In impressionistic, diary form he ruthlessly catalogues his every feeling and sensation about the world and people around him. His thoughts culminate in a pervasive, overpowering feeling of nausea which "spreads at the bottom of the viscous puddle, at the bottom of our time--the time of purple suspenders and broken chair seats; it is made of wide, soft instants, spreading at the edge, like an oil stain."
Nausea by Jean-Paul Sartre.
The Prince by Machiavelli.
Categories by Aristotle.
We should really stop making reading the holy grail of sophistication. It's not inherently better than any other type of media.
Unless you're actually trying to learn about new stuff and read non-fiction, it's not like books will 'give you' anything that watching movies can't give you. For relaxing it's most important that the thing actually relaxes you. Feeling like you have to read books sounds a little backward.
If you want to force yourself to get in the habit of reading, it's best to plan a time for it (outside of your relaxation time!). Maybe plan to do it each day for 30mins after dinner. This way after you finish you still have time to unwind your day (without having to worry about having to read books).
edit: for fiction I recommend the hitchhikers guide to the galaxy, any of the Murakami books, Nausea by Sartre, or Zen and the art of motorcycle maintenance. For non-fiction: I recommend picking any topic you're interested in. Skip the biographies and self-help/guide books, they'll only guilt trip you