Must have freebie programs to protect and clean

[tandar]

I would still recommend a software firewall on your system. There is a vast difference between a stand alone hardware firewall, and the firewall built into a router.  While a router's firewall does offer a good amount of protection its mostly from inbound connections. It won't stop connections initiated by your system if it becomes infected with a virus, whereas a good software firewall will.

[James]

I suppose to each their own on this. So long as you have a good anti-virus and have it set to auto run once a week (or more often if you wish), all should be fine. The problem I found with firewalls was that they were hogs on the system, and for those who do not have gaming PCs, using that much RAM at all times is not a helpful thing at all.

[dnavia]

if you use windows 7, the built in firewall is just fine for the average user. I've used all the major firewalls (zonealarm etc..), and the win7 one is just fine for my use. between that and my router firewall I feel quite protected.

[ccrashh]

Avast and AVG have become massive resource hogs.  You might want to have a look at Avira.

Also, to protect your PC, try using Sandboxie.  It's a great tool and "...runs your programs in an isolated space which prevents them from making permanent changes to other programs and data in your computer."  Very handy. 

[Chris]

@ccrashh ahh I forgot about Sandboxie it was a nice program to isolate files you run if your not so sure about them. It's been a while since I used it but it was great when I did.