There are a few things that could be improved, however.
I would recommend not blindly copying the sysctl values provided. Many of them were already set higher by default on my test system. By copy/pasting the suggested values, I was actually lowering the values (maxfiles, shared memory settings, etc.).
Another big one was device permissions. For a single-user machine, they're probably okay. If another person will ever have access to your machine, however, you're probably granting them way too many permissions.
In short, if you're just wanting to bring up a FreeBSD desktop to play around with, this will probably get you there. You might also consider PC-BSD [0], which takes of all the hard work for you.
Once you're up and running, head over to the FreeBSD Forums if you encounter any issues.
Welcome to FreeBSD!
[0]: http://pcbsd.org