I really enjoyed Designing Design by Kenya Hara. Lay it on me, DN.
»Universal Principles of Design« – Not inspiring per se, but very, very useful.
Design and Form: The Basic Course at the Bauhaus and Later, by Johannes Itten Design for the real world: human ecology and social change, by Victor Papanek
A few colleagues and I have made a Pinterest board with some of our favorite design books. See: http://pinterest.com/jedmund/design-books/
Sketching User Experiences, Bill Buxton and I second the earlier note about Thinking with Type, Ellen Lupton
My must-reads are Josef Müller-Brockmann's Grid Systems in Graphic Design, and all of Kimberly Elam's books.
Type, Image, Message by Tom Wedell and Nancy Skolos
The Elements of Typographic Style by Robert Bringhurst
I agree with Dan, Munari's "Design as Art" has an inspiring collection of essays I keep going back to.
I always find Robin Kinross's books incredibly interesting as well. Even though they aren't entirely about the practice of design, both "Modern typography" and "Unjustified texts" are invaluable resources. Actually, anything published by Hyphen Press is worth a read—they've also published quite a few of Jost Hochuli's books on typography and book design.
Design by Nature, of Maggie Macnab, was my greatest found from 2012. An amazing and super inspiring book.
Frank Chimero's "The Shape of Design" was a real delight to read. Very uplifting and inspiring. http://www.shapeofdesignbook.com/
Ah, yes! Very good one. +1
Yes, definitely a must-read!
Also more on the practical side, if you're dealing with clients, reading the "Design Is a Job" by Mike Monteiro is a no-brainer. http://www.abookapart.com/products/design-is-a-job
"Thinking with Type" by Ellen Lupton.
Any Dieter Rams / Naoto Fukasawa books with sexy pictures. Strictly industrial design, but inspiring nonetheless.
making & breaking the grid was a standby when i was younger
I enjoyed reading "The Design Of Everyday Things" by Donald Norman. It's a must-read.
I started reading that as part of an essay for uni. Think I'm going to have to go over that one again. What I read was great.
I love Bruno Munari's "Design as Art" :)
haha i read that as "bruno mars" and was like wtf?