Research-Based Web Design & Usability Guidelines. Want a concise encapsulation of issues pertaining to usability and web design? Look no further than this (free) book from usability.gov. This is a thought provoking, easy-to-digest read that should be required reading for basically anyone that works on the web.
For what it’s worth, I did a redesign of my home page based on some of the guidelines and after a couple of weeks I’ve seen real improvement in home page performance. I’ll post a case study in a few weeks, once I have a larger data set.