Gill, Bob, Forget All The Rules You Ever Learned About Graphic Design, Including The Ones In This Book.
New York, 1981, Watson-Guptill
ISBN 0-8230-1863-6
Unlike most books on graphic design, this one talks about how to think, concept, and problem solve.

MacLeod, Scott, Understanding Comics: The Invisible Art.
Kitchen Sink, 1993
If you're a visual communicator, you'll get something out of this thoughtful foray into the world of comics – all told in comic-book form. Very enjoyable and instructive.

Pye, David, The Nature and Art of Workmanship.
More about object design but also applicable and everyone should read – also his "the Nature of Design."

Shahn, Ben, The Shape of Content.

Rand, Paul, A Designer's Art.
Yale University Press, 1985
Essential book on design.

Thompson, D'Arcy, On Growth and Form.  
Design in nature, get the abridged.

Tufte, Edward R., The Visual Display of Quantitative Information.
Cheshire CT, 1983, Graphics Press

Tufte, Edward R., Envisioning Information
Cheshire CT, 1990, Graphics Press
(Box 430-Y, Cheshire CT, 06410)
ISBN 0-9613921-1-8
Both should be required reading for all graphic designers.

Venturi, Robert, Complexity and Contradiction in Architecture.
Pluralism versus modernist formalist purism – addresses architecture but applies easily to 2D... can't think of a book nearly as good specifically for graphic design.


More....

Mark Choco, Le Design au Québec
History of design in Québec

Poppy Evans, Forms Folds Sizes, Rockport 1-59253-054-0

Jim Krause,  Design Basics Index: A Graphic Designer's Guide to Designing Effective Compositions, Selecting Dynamic Components & Developing Creative Con

Tim Krause, Design Basic Ideas, How Design Books 1-58180-501-2

William Lidwell, Kritina Holden, Jill Butler, Universal Principles of Design: A Cross-Disciplinary Reference

Mark Oldach, Creativity for Graphic Designers, North Light Books 1-58180-055-X

Paula Scherr, Make it Bigger

Adrian Shaughnessy, How to Be a Graphic Designer, Without Losing Your Soul

Robin Williams, Robin Williams Design Workshop, (also has great advice on project management and managing client relationships)