Hi
In addition of Steve Recommendation to use SSG5 , you need 2 boxes to practice clustering NSRP , (extended license required)
it is not bad idea to use it for your home network , I am using SSG20/Wifi model , and oblige all in my home to pass through it , I block some URLs for my kids using webfiltering , and also I can enable UTM features on it , I can monitor the session count and can also know if which host in my network is consuming bandwidth and may be part of botnet .
Regards