How about a completely new approach to file system / data management? I am always excited when the old is thrown away and something new is built in its place. The ZFS file system is just such a beast. If you are unfamiliar with this file system, here are some of the benefits I got excited about:

Storage is represented as a pooled storage where files systems draw from this common storage pool, and each file system using only the space it needs. Because of this shared resource, all file systems have the same I/O resources available to make use of and level out performance. Storage pools can serve up volumes explicitly for raw devices.

RAID-Z: Similar to raid 5 but eliminates stripe corruption with a variable stripe width, removes the need for NVRAM in hardware, and allows for disk scrubbing to detect and correct errors-enabling you to make use of very cheap disks.
Support for snapshots and clones-allowing for incremental and full backups through the use of those snapshots. So you can make point in time copies of the filesystem with writable clone copies.

There are many more nice features but these just sort of stuck out to me as unique and groundbreaking. Not that some of these technologies haven't been around. I mean, almost all vendors have snapshots and various RAID levels. But you don't get them for free.