Listmania!
Interaction + Interface Design
By an Amazon.com customer
About Face 3: The Essentials of Interaction DesignAbout Face 3: The Essentials of Interaction Design by Alan Cooper
Buy new: $29.70 / Used from: $18.90
A must have ... really.
The Laws of Simplicity (Simplicity: Design, Technology, Business, Life)The Laws of Simplicity (Simplicity: Design, Technology, Business, Life) by John Maeda
Buy new: $11.74 / Used from: $7.75
A very good, quick and inspiration read. Do yourself a favor and get this ... oh, and a great gift idea, too. Order a box :)
Designing Visual Interfaces: Communication Oriented TechniquesDesigning Visual Interfaces: Communication Oriented Techniques by Kevin Mullet
Buy new: $54.63 / Used from: $9.00
A must have, too.
In the Bubble: Designing in a Complex WorldIn the Bubble: Designing in a Complex World by John Thackara
Buy new: $12.89 / Used from: $7.99
Tough read, but great context.
Designing InteractionsDesigning Interactions by Bill Moggridge
Buy new: $24.01 / Used from: $15.45
Envisioning InformationEnvisioning Information by Edward R. Tufte
Buy new: $23.04 / Used from: $13.50
Sketching User Experiences:  Getting the Design Right and the Right Design (Interactive Technologies)Sketching User Experiences: Getting the Design Right and the Right Design (Interactive Technologies) by Bill Buxton
Buy new: $27.93 / Used from: $14.54
Haven't gotten through the whole thing yet, but it's proven very useful already.
Information Anxiety 2 (Hayden/Que)Information Anxiety 2 (Hayden/Que) by Richard S Wurman
Buy used from: $13.00
A Pattern Language: Towns, Buildings, Construction (Center for Environmental Structure Series)A Pattern Language: Towns, Buildings, Construction (Center for Environmental Structure Series) by Christopher Alexander
Buy new: $40.95 / Used from: $29.00
a Classic.
The Timeless Way of BuildingThe Timeless Way of Building by Christopher Alexander
Buy new: $40.95 / Used from: $37.28
The Works: Anatomy of a CityThe Works: Anatomy of a City by Kate Ascher
Buy new: $13.60 / Used from: $8.40
I reference the visual design of this book if for nothing else but inspiration.
The Inmates Are Running the Asylum: Why High Tech Products Drive Us Crazy and How to Restore the SanityThe Inmates Are Running the Asylum: Why High Tech Products Drive Us Crazy and How to Restore the Sanity by Alan Cooper
Buy new: $16.29 / Used from: $9.55
I guess this is dated now, but helped set the context for 'About Face', a long while back.
Orbiting the Giant Hairball: A Corporate Fool's Guide to Surviving with GraceOrbiting the Giant Hairball: A Corporate Fool's Guide to Surviving with Grace by Gordon MacKenzie
Buy new: $14.96 / Used from: $4.94
A very fun read ... doesn't teach about design, but teaches you how to survive as a creative person in an otherwise conservative, large corporation.