And now for something a little different.
If you are working with any type of media that presents information to a reader, be it a web site or even a book, you should check out: http://bootstrappingdesign.com/
Author Jarrod Drysdale gives practical design advice which I found invaluable. It is also very well written and a pleasure to read.
The book is available via download and includes PDF, .mobi, and .ebub formats.
So, if you are working on your own web site, writing a book, or just want to enhance your design skills, then you should add this book to your collection.