More and more Internet faceing sites are taking on Sharepoint 2007 as a platform. Check out this (Sharepoint 2007) site that showcases a number of public sites that are on Sharepoint 2007.
Aside from site references, you'll also find a number or articles and learning resources if you want to find out more about the platform. It also contains a number of demos on rendering Excel documents and Gantt Charts. Check it out!