I have found that one of the most important skills as a designer (or any career, really) is to be resourceful, knowing where to look for everything one would need. Whether it's finding the perfect typeface for a branding project, or a book to spark some new ideas.
Definitely one of my all-time favorites. I read this before my first internship in Seattle and learned oodles of design knowledge.
Never Sleep: Graduating to Graphic Design
Recommended to me by one of my professors in college.
Required reading in my BFA program. Debbie Millman is awesome. Her podcasts are a must listen as well.
The perfect little inspirational book.
This publication is a must for anyone who is passionate about pursuing their dreams (which should be everyone). They're online site is a great resource as well. I always read a few of these interviews when I need some encouragement and a little pick-me-up.
I read this book for my independent study in college on Design Entrepreneurism. An amazing publication that includes interviews with 30 leading designers and discusses what it takes to run a successful business and build your career.
One of the most important attributes to have as a successful designer is the confidence to vocalize your thoughts and thinking. Authors Tom & David Kelley help teach us how to unleash our own creativity and innovative spirit that lies in all of us.
Roger Martin discusses why thinking like a designer is the next competitive advantage to benefit any individual or company in today's modern, innovative and technological world.
*This site has a great list of traditional books on Graphic Design & Typography as well