Things aren't looking good for
ZFS, Sun's jaw-droppingly impressive next-generation filesystem, used in Solaris and once slated to appear in OSX; now
Apple have abruptly shut down their open-source ZFS project. There is speculation
here that it has to do with (a) Oracle, who bought Sun, already being behind a competing (if currently somewhat less developed) filesystem,
Btrfs (which is being developed on Linux), and planning to kill ZFS development to rationalise costs, and/or (b) server manufacturer NetApp suing Sun over patented technologies used in ZFS.
Apple, meanwhile, are hiring filesystem engineers, which suggests that they're planning to build their own next-generation filesystem. Until then, Mac users will have to make do with HFS+.