Apple is going to use Sun's Zettabyte File System in its next Mac OS X version, code-named Leopard.
This is the first OEM for Sun's ZFS which is a radical extension of existing filesystems and their approaches to file management. ZFS protects all files with 64-bit checksums to detect and fix data corruption. As a 128-bit file system it can handle many orders of magnitude more space than current versions of Windows, OS X, or Linux. ZFS virtualises disk drive space into a single pool so you don't need separate storage virtualisation software. It provides file snapshots and does RAID too. So a lot of what we might call storage management services get automated and put into the filesystem itself. There is an effort to port ZFS to Linux but GNU General Public License restrictions are hindering it.
For customers it means a single file system can handle billions of files, assign space to applications automatically, grow by just adding disk drives with no storage admin needed to add them to the pool of usable capacity, and protects data by file snapshots. No other file system comes close.