Don't forget the fact that your users will be thousands of miles away from your server, and downloading dozens of files to render a single page. That latency, and the overhead of rendering the page in their browsers can be larger than the amount of time that you spend collecting the information, and generating the page.
See the pages at Yahoo Developer Network about Best Practices for Speeding Up Your Web Site, and the YSlow tool for seeing what part of the downloading of the site is taking time.
