Firewall, antivirus ...everything are rendered useless if the user doesn't even care on how to take care of his/her computer.
The Windows Firewall that came along with Windows 7 is quite enough to protect your computer, as you can also allow/disallow any programs for connections.
But, if you still want to use 3rd party firewall, I'd recommend either
- PC Tools Firewall Plus - Free Firewall Download
- Antivirus Firewall Software and SSL Certificate - Internet Security Software from Comodo
Well, practice safe computing~