I've spent a couple hours digging back into the new WinFS. So far it seems interesting, but only as a new datastore. It doesn't seem to be trying to be the Object File System from teh Cairo days, though that may be because of it's bolted-on status on XP. It is still stored in a SQL Server engine, so that is good. It also looks like the actual files (not just the metadata) are being stored there.
I will probably update my WinFS DB Explorer and release it next week with the new bits. Being able to look at the DB would be fun!