From Fedora Project Wiki
File Systems
eCryptfs
While Fedora 9 debuted encrypted fileystem support, Fedora 10 builds on that and fixes a number of problems that could have resulted in data corruption.
EXT4
Fedora 9 debuted a preview of ext4 support. Fedora 10 brings a fully ext4-compatible e2fsprogs. In addition Anaconda's partition screen has an ext4 file system option available if you launch the installer with the ext4 option. To do this, enter "ext4" in the installation boot prompt. Fedora 10 also brings delayed allocation for ext4. However, ext4 in Fedora 10 doesn't currently support file systems larger than 16 terabytes.
XFS
XFS is now a supported file system and an option with the the partitioning screen of Anaconda.