Even just labelling partitions alone on GPT made things much easier for me. No more hoping da0 still scans as da0, oe having to remember a UUID.
What the purpose/mount point of a partition is (i.e. is this a /home/ partition or a root file system?)
Shall this partition be mounted automatically? (i.e. without specifically be configured via /etc/fstab)
I see wonderful things about to happen for people who have more than one distro installed.