ASUS M2NVM HDMI seem to work fine.
Had to update bios to latest version 0702 otherwise I recieved these nv_nic_irq messages which as known problems with many nforce based motherboards.
Before bios update video freezed for a second or so and then continued every 10-20min, at the same time the nv_nic_irq message was shown in dmesg.
After bios video is smooth.
This card have the same audio chip that nite_man is showing on his blog, smart-home-blog.com (except is have nvidia instead of ati).
The onboard azalia sound chip is able to output audio through onboard hdmi conector.
The other AC883 audio chipset work out of the box (at least for stereo sound which is how far I have tested it yet).
Will move the system into my livingroom to test it with dts and dolby digital soon. Hopefully I can test audio over hdmi against my panasonic plasma too.
Did you use on the onboard video card with the M2NVM-HDMI? If so, what video drivers did you use? I have this board and I am going to build my MD this weekend.