Single Board Computer Firewalls

Since a couple of days I have been reading a lot about SBC (single board computers) based firewalls. I have found Soekris and WRAP boards interesting and I think I will get one in the future.
I like the idea of having this low power little boxes as a firewall. They are completly quiet boxes, fanless and with a CFs (compact flash) cards instead of hard drives.
Most people use them with m0n0wall, a FreeBSD based firewall, so I think I will take a look at it before anything else, just to see how good it is. And it's also a good excuse to get my hands on FreeBSD too. :-)