Desktop Google looks promising
...especially the integration with web search and your browser's cache. That means a personal Feedster from trolling my Bloglines page-reads. Nice!
I'm underwhelmed by the application support (AOL-IM, Office - yes, OO/Mozilla/Trillian - no) but to be fair it's probably what I would have started with if I was the product manager.
Also, I can see why they wouldn't support things like Mozilla/TBird -- when they add gmail integration, you can just write a forwarding filter or bcc rule to mirror your mail stream on GMail's server to get non-Outlook mail-searching goodness.
But, without support for the Firefox cache, my index is going to be restricted to lame sites that require flash. I hope they fix that soon.