COMODO Personal Firewall...
I was using Zone Alarm till yesteryear. But the new year brought in COMODO.
Read some reviews:
*www.iopus.com/guides/free-firewall.htm
*www.all-internet-security.com/top_10_firewall_software.html
*www.pcmag.com/article2/0,1759,1969207,00.asp