Building optimized sites has always been a major part of our strategy: they are easier to maintain, easier to upgrade, and they load more quickly. I have never built a site using only Flash, and have always built sites using HTML-and-CSS based navigation menus. They are search engine friendly and easy to expand or rearrange.
With that in mind, I have recently come up with a few other ways to speed things up. A faster site will generally rank better in the search engines, plus it will have less people abandoning the site while waiting for it to load.