The Best Firewall ?
As far as software is considered I would recommend Checkpoint it is the best software firewall period but you gotta pay but if your looking for a free firewall then get Comodo Firewall
As Far as Hardware is considered I would recommend Astaro
Router firewall (built in) is decent but I feel that the more protection the better :)
Monowall ? Never used it , but googled it and 'A free embedded firewall software package based on FreeBSD' that right there tils me it is probably good
Windows Firewall ? Honestly, that is a joke
ZoneAlarm, is good but the problem with Zonealarm like Windows is that is has been known to get easily bypassed it just to bit risky
Smoothwall is good
Sygate Personal Firewall is decent