Socket 939; nForce4-4x chipset; AMD Athlon64 3000+ CPU
I had to disable (in BIOS) the USB mouse and keyboard (use PS/2 instead--USB with a PS/2 adapter won't work either) in order to install eCS 1.2R, but was able to re-enable and use a USB keyboard after the install (haven't yet tried the USB mouse).
UniAud driver works well with onboard sound (AC97). I haven't found a driver for the onboard LAN (Vitesse 8201 phy--never head of that brand), but it can be disabled in BIOS in order to use a NIC (mine is a 3Com).
I haven't tried the RAID, SATA, or Firewire, but I understand that Dani's drivers (on Hobbes) will work with these.
Very clear, polite (lots of "please") user's manual. :)