help choosing a motherboard

Guys I wonder if anyone has any motherboard they would recommend...

I am building a network of Linux machines that will...
- behave as routers / WLAN access points / LAN-over mains switches
- stream audio to and from each other

The first thing to do is choose which motherboard to buy.

My target spec is now...

- audio SPDIF header which has input pin as well as output pin
- well suited for desktop Debian Linux
- very common chipset to ensure compatibility
- doesn't have to be high performance
- low cost
- known to be sold in high volumes / commonly used so plenty of Linux drivers
- ideally dual (or more) LAN ports

Anybody have any suggestions...?

Thanks in advance,
Doug.