While re-designing my website, I came across a couple of sites that I believe you may find useful. BuiltWith (http://www.builtwith.com) and Website Grader (http://www.websitegrader.com).

BuiltWith is a website analysis tool, providing technical analysis and SEO optimization information to further your website's marketing, sales and navigation effectiveness. Website Grader on the other hand, is a free seo tool that measures the marketing effectiveness of a website. It provides a score that incorporates things like website traffic, SEO, social popularity and other technical factors. It also provides some basic advice on how the website can be improved from a marketing perspective.

For any web designer, I feel this is pretty useful.