Can you harden a linux system as good or better than a cheap
hardware
firewall, you may be able to today, someone new maybe not.
Well, there's always firewall-specific distros - smoothwall and the like. I'm
pretty sure a newbie could work out how to set up a hardened Linux network in
less than 10 minuites with a Smoothwall CD. Ok, that's slightly cheating
because it's turning an old computer into a cheap hardware firewall.
Besides, I've always thought the default security with Redhat/Fedora was
pretty good. Just not selecting any services to let through the local
firewall in the graphical installer should be good enough.