I have recently stumbled upon SmoothWall Express 3.0 SP1. I am getting down-right giddy thinking about all the neat things I can do at home with this thing.
SmoothWall Express is a stand-alone, open-source firewall project. It has a large, active community full of helpful people. Some of these helpful people create mods to extend the functionality such as the ultra useful Full Firewall Control mod.
In my experiments I was able to create a very tiny box with two NICs, little RAM (256MB), a spare Pentium 4 I had laying around, and a 2GB Compact Flash card as the local storage. This poor excuse for a machine was able to stand up to some pretty heavy traffic– without ever passing .25 load, mind you– including a few test torrents totaling over 1,000 connected peers.
My ultimate goal is the separation of all traffic according to use. I might have one public, outward-facing interface for the Internet connection and three inward-facing interfaces for the local traffic (private wired, private wireless, and an internal DMZ). I also plan to build a beefy VMware ESXi box so I can sandbox each of my services (vpn, web, SQL, e-mail, ect) and do nearly all of the networking within virtual hardware.