There's an interesting piece of advice at the bottom of this post - the author symlinks /bin, /sbin, and /lib to /usr/whatever. Anybody else have an opinion on that practice? It's kind of unnecessary, but it also doesn't break anything.
The Fedora move is why this link got posted and is getting upvotes.
$ for f in /bin/*; do [ -e "/usr$f" ] && echo /usr$f; done;
/usr/bin/dumpkeys
/usr/bin/ksh
/usr/bin/less
/usr/bin/lessecho
/usr/bin/lessfile
/usr/bin/lesskey
/usr/bin/lesspipe
/usr/bin/loadkeys
/usr/bin/mail
/usr/bin/nano
/usr/bin/tcsh
/usr/bin/touch
/usr/bin/which
/usr/bin/zsh
FreeBSD's default install creates: /, /usr, /tmp, /var and swap space.
When you boot in single-user mode all you get is / and nothing else. If everything was in /usr you wouldn't be able to mount /usr ... :P
See man hier [1].
For example, on a FreeBSD install, it is perfectly safe to rm -rf /usr/local/. Your system will still boot without issues.
[1] http://www.freebsd.org/cgi/man.cgi?query=hier&apropos=0&...