AVG + Firewall is basically just the crap of Kerio modded to fit in with the AVG GUI
The problem with combo antivirus/firewalls is that either component is usually not made by the same company
Examples:
Zonealarm w/ Antivirus = Zonealarm firewall / Mcafee antivirus
AVG w/ Firewall = AVG antivirus / Kerio firewall