I basically sent the same question in an e-mail to Amy Hoy last night. She recommended these two books, "The Universal Principles of Design (have to get a used copy) and About Face 3 for interaction design."
I own The Universal Principles of Design, and it's an excellent book. Each pair of pages has a description of a principle on the left and some examples of it on the right.
About Face 1 and 2 where seminal works, the editing in them was poorly done but the content was some of the best available at the time. This thread got me looking at books again and I realized that 3 is the latest work. So I picked up a copy to see how it is. I duly expect it to be as good, here is to hoping that the editing is better in 3.