So I played with Sophos a little bit and it is very nice, but complex as well. I may be able to play with it some more this weekend but after a long day at work sitting in front of a computer, i find it difficult to sit in front of a computer much longer except to check a few emails.
Right now I need to do a little research on system components which will easily support the throughput of my household for the future, not just today, and to ensure it can handle running the Intrusion Detection System software which is here the major overhead comes in. So, I need to figure out the CPU horsepower and how small I can make it. Luckily I don't need ECC RAM ! However, if the system can use ECC, it would give me a fallback system for my FreeNAS. And of course low power is key, I'd like to have passive cooling as well.