The personal level is probably okay for almost all home users.
You would need to use the the Enterprise protocol if you are supporting a lot of VPN access to your PC for gaming, or Wide area network with shared productivity using A.S.P. (Active Server Protocol.).
The enterprise level is very difficult to set up correctly, and if not done right, it can leave you very vulnerable to hackers. The security is a lot stronger, but to work right, it is hard to set up.
You probably should use the personal setting unless you have a specific need for the Enterprise support.
Once you set up the router, go to http://www.symantec.com and get a free port scan and security check up. If the security scan findes anything wrong, it will tell you so you can fix it.