I’ve been spending some time playing with WinFS lately, and I simply cannot wait until there is real support for making your own types to store.  I hope that with the real beta that WinFS will be more fully functional.  I can see some impressive things that you could do with WinFS by using it as a local data store.  Not just a local data store, but one that can interact with everyone else’s data.  I’ll be reporting more regularly on my WinFS observations in the coming weeks.