WinFS isn't a feature of Longhorn. It's been pushed off till later (again). Microsoft has been trying for a long time to do what WinFS wants to do, dating back to some of the promises of NT 4, then NT 5...

If you want to see what Apple has working already, look at Spotlight. Or for a video demonstration, tune into this and go to the 0:42 mark. Make sure to watch the entire segment on Spotlight, as it shows some innovative uses of it beyond files.

What this does is actually quite useful. And none of it gets rid of a file structure. Instead, it very quickly allows me to find any document on my system that talks about the empeg, even if it is named 20394.doc, or if it is in my instant message logs.

The general thought behind this all is "Why can we get search results back from Google on things faster then finding files on our own systems?"