Currently running two frontends:
1. Silverstone LC11-M case (two quiet fans). DVI+digital coax @ 1080p.
For DVI output: MM_X_OUTPUT_DVI='auto' (I assume the actual value is zero)
For digital coax audio: MM_AUDIO_DEVICE_NUMBER=1
2. Serener GA-L01 case (fanless, noiseless). HDMI for video+audio @ 720p.
For HDMI video: MM_X_OUTPUT_HDMI='1'
For HDMI audio: MM_AUDIO_DEVICE_NUMBER=3
For both devices:
Both units have 2GB (2x1GB) DDR2 800.
(I haven't used the Serener frontend much, so the following notes apply to the Silverstone case)
Without VDPAU, SD programming plays flawlessly but it stutters at 1080p. With VDPAU I haven't had a problem with any resolution source video. Power usage for the whole box ranges from 45W at idle to 50W under load. CPU temps from 34C to 46C.
Now the downside: Hulu video plays at the bottom edge of watchability, perhaps 3-5 fps. This seems to be only slightly improved by selecting low quality video. I'm told this is generally due to the poor performance of the flash plugin, and in particular lack of support for VDPAU. Some research led me to believe it would be included in version 10.1 of the flash plugin. However, no improvement was found after installing the latest beta. But then again, I'm not completely certain I installed it correctly.
Overall this motherboard has met my expectations. Previously I had completely different hardware on each frontend, which meant that after upgrading I would sometimes miss problems on the seldom-used Serener frontend (it was previously occupied by a Via Epia SP8000E). With identical hardware, I know that if one is happy, the other is too. Also, if I ever want to add another frontend I know the mini-itx layout will give me ultimate freedom in case choice. For a while I was a little frustrated with Hulu, but now that they dropped Daily/Colbert it turns out I don't really have a use for it.
If anyone has any questions, let me know.