I almost never go to Google home page these days: I use a bookmarklet to directly go to Google results page instead. However with their suggest feature, Google has convinced me that it's worth it to go again to their homepage.
Now a RFE for Googlers: I'd like is to have this suggest feature in GMail when I do a mail search. I type
from: in the search field and GMail should suggest me a list of senders. That'd be cool and useful...
Google is not the first web site to make extensive use of XmlHttpRequest but they show how it can be done to enhance the web experience. As more developpers become aware of such functionalities, it will create a new breed of web applications which extend the web experience by embracing its principles rather than just mocking desktop applications within the browser.