In Seth Godin's recent blog posting, 'Things to ask before redoing your website', he hits the nail on the head!
Make sure you not only read this posting, but ask the questions and better yet, answer them ---- before you redesign your website (not after)!!!
Also, I recommend picking up a copy of his book The Big Red Fez. It's a must-have when thinking about how best to design your website with analysis of actual screenshots of live websites.