There’s a lot of buzz about the Zettabyte File System from Sun Oracle, which has been included for a while in both Solaris and OpenSolaris. (Distributions based on Opensolaris like Nexenta have it. Also some BSD distributions have it).
In general, file systems are not exactly glamorous. HFS? UFS? VxVM? Who cares. It’s a file system, right?
ZFS has some serious juicy goodness. Personally, I think as time goes on, you’ll see more and more ZFS (or at least ZFS-like file systems) used on production servers, especially file servers. Like NexentaStor.