Adaptive Web Design by Aaron Gustafson is yet another self-published book (yes, I know, you spent all your money at Five Simple Steps and A Book Apart) that looks like a good read. Even if you don't buy the whole book, you can download chapter 1 for free.
Perhaps late-night surfing is not such a waste of time after all: it is just the Web dreaming. Tim Berners-Lee
Currently listening to: Script of the Bridge by The Chameleons