These are some of the mostly nontechnical, nontextbooks which I've enjoyed reading. Maybe there are a few ideas for your own reading list.

• How to Solve It
• Mathematics and Plausible Reasoning
• The Art and Craft of Problem Solving (Paul Zeitz)
• Pilgrim's Progress
• The Courage to Be Disliked
• The Inner Game of Tennis
• Zen and the Art of Motorcycle Maintenance
• The Lord of the Rings
• Beowulf: A Metrical Translation into Modern English (John R. Clark Hall)
• Kalevala