I've been reading Jef Raskin's _The Humane Interface_ and have been thoroughly enjoying it. Raskin write in lucid style which nicely compliments his theories and assertions. But the chapters about UI efficiency are, imho, a bit extreme in their faith in the GOMS model which is a purely quantitative measurement.
A UI that should do everything it can to merely reduce the amount of time it takes to do thing is a story without a plot. Ease of use != speed of use. But efficiency is still a concern, but probably more so for government forms than for websites where issues like marketing and branding are important.
The bottom line though is that this 'fundamentals' book is a must have if you are a UI developer or designer and want to produce successful web sites/applications.