This is nice indeed, but the large majority of new computers seem to come with Home Premium, which is not eligible for the downgrade (upgrade? 
).
m0n0wall is based on FreeBSD. Watch out, BSD fans get angry when you think its linux! You might also want to check out pfSense which is based on m0n0wall. It seems more 'friendly'. I've used it as my home router/VPN server for about a year now. Easy to config, and I never have to touch it at all. It is the most rock solid PC I have. I think it has 300 or so days of uptime.