A true database-driven filesystem. WinFS should have happened by now. A true database-driven file system would make searching lighting fast, and more importantly, more customizable. Building indexes off of drive data is slow and cumbersome, and then querying that index is also slow and cumbersome. The entire process would be much more efficient and extensible were it centered around a database-like filesystem, complete also with journaling. I firmly believe the benefit of metadata in the everyday computing experience will not be realized until filesystems are more akin to databases.