What can I say? 67% drivers (the bulk of which is from 'staging', but there's driver changes all over), 10% firmware, 10% arch updates dominated by arm, but MIPS, POWER, SH and x86 updates are there too,¬† along with the new 'SCore' architecture), 5% Documentation, and a random smattering of other things (ie the normal filesystem, kernel, networking etc updates).
For a change, I don't think we have a single new filesystem this time around, but we do have updates to existing ones (ocfs2, btrfs, nfs, nilfs, fs, gfs2, ext4 - you name it).
Some of the more interesting changes (but perhaps that's just me) are some of the VM updates (ZERO_PAGE is back!) and the writeback work by Jens and others to spread out writeback by backing store.
Go wild, test it out, and let us know about any regressions you find,