Netvibes
In case you have not already seen it, you should definitely check out Netvibes. This site is implementing a basic version of what I consider to be the next generation of human/computer interaction. The web-desktop offered by Netvibes is user-friendly, functional, and aesthetically pleasing.
What I have done is set Netvibes to be my desktop wallpaper through Microsoft’s long forgotten Active Desktop feature. Because the site uses AJAX, there is no need to set a manual page refresh schedule (one of the many reasons that Active Desktop was a flop). Instead, various portions of the Netvibes page will periodically update themselves using asynchronous javascript.
With Active Desktop, the Netvibes page has no borders and is locked to the desktop background so that it never gets in your way. You can, however, still click on the various parts of the page as if you were in a standard web browser. Take a look at this screenshot for a better idea of what I mean:
