Vista's built-in firewall is perfectly adequate for most people. While
it's not quite up to the ease-of-use standards of Kerio or ZoneAlarm, it
has been noticeably improved over WinXP's version.
There are two interfaces for Vistas built-in firewall:
1) A simplified one accessed through the Control Panel that is the only
one most people see. To further supplement this view, Sphinx's Vista
Firewall Control
http://sphinx-soft.com/Vista/) is a piece of freeware
that makes the Vista Firewall much more easily manageable to the average
user.
2) And the more advanced "Windows Firewall with Advanced Security
(WF.msc), accessed via the Start Menu's Administrative Tools folder, for
the experienced user who wants more granular control.