At any rate, I started putting together an overview of the field, and come up with the stuff you see below. I found it pretty interesting to see what I included and what I didn't...
Usability is a varied field under a parent field called Information Architecture (IA). The most well known and controversial Usability person is Jakob Nielsen who's AlertBox is usually a good read and offers practical advice. Im my opinion, Nielsen is the Pat Buchanon of web design due to his somewhat right wing, reactionary and rigid rules. He's a scientist, not an artist.
Nielsen has several books out on the market. The Designing Web Usability book is pretty good, and is a common sense guide to good usability. His other, more recent book is a good visual guide to the mistakes of others, which helps you avoid those mistakes in your own work.
Raskin wrote a great book called "The Human Interface" that is academic, but approachable and very readable. He gets bogged down at times in interface efficiency which I think is a low priority in commercial web design (my opinion!). For applications that involve repetitive tasks, Raskin is a great person to look to for help on designing humanely. but again, he's not a visual designer. Neither is Tog, even though he worked with Apple on the Mac interface back in the good ol' days.
Cooper is the stand out in my opinion. His company is an IA firm that offers help on designing apps that are usable, attractive and user centric.
Morville and Rosenfeld wrote the seminal book on usability and IA called "Information Architecture". I own it, and when I read it, I knew everything already, but it was great to see all of the basics encapsulated in one book. Another book called "Web Navigation: Designing the User Experience" is, in my opinion, a sister to the IA book. Both should be read and understood thoroughly by any User Interface professional.
Nathan Shedroff wrote Experience Design which is a nice visual book that present examples of design experiences, which are not always web based. I really like Nathan's style and subscribe to his preachings. Recently, he was the lead IA on the new Herman Miller Red site.
Jesse James Garret has produced a visual Vocabulary for interaction design that I have slowly adopted in my work at WebCritical. I've made my own modifications to it, but it works as a flow charting language that is tailored to the needs of the web interaction designer.
Beyond these people there are MANY other resources on the net that can be of help to the Information Architect. I won't bother listing them all here, because Garret has a nice list available on the web. But it doesn't mention 37signals which has a good periodical about good and bad design on the web.