I run it as my only software firewall, a backup to my DLink Routers built in firewall

But before I had the router I used it as my standalone firewall, I was personally very happy and protected by it.... Zone Alarm is probably the worst you can get though due to its incapability to deal with some cable connections plus its not the greatest for protection... Norton is also complicated for newbs (my grandmother always complained) and is repitive in asking if the connection hsould go through if you say yes and lock the option

Sygate is good also