Best firewall to use for Linux, something like ISA?

Im really tiered of windows and ISA…their expensive and heavy….not really suitable for a small business..

I want to implement a Linux NAT firewall.

But im so used to ISA because its very nice and graphical…especially the reporting system.

Is there any firewal that offers a consol…(cpanel, plesk, webadmin) something like that to configure it and produce reports and statistcis that are as good as ISA….silly me for ever comparing anything linux has to offer with Windows ISA…

All i want is the basics.

Application Signature Filtering..
etc….

But the reporting on ISA is really good….