I've read the excellent Getting Real by 37 signals online and haven't been disappointed by their Defensive Design for the Web. In the real world things go wrong and you can't prevent every error, but you can handle them properly. It's not just a book for coders or webdesginers either, I'd recommend it to anyone making decisions about site design, layout or functionality. The book covers topics from usability to copy writing using easy to follow, real world examples of websites getting it right, and other getting it wrong.
Defensive Design for the Web from amazon.com[[posterous-content:AJDusccCJIbGkhvldmlk]]
Defensive Design for the Web from amazon.co.uk[[posterous-content:onvzDbnnxwGbCJGbzskH]]