This page describes the step necessary to get all of the features of the ASUS AT3IONT-I [Deluxe] working correctly. It assumes you already successfully installed Arch Linux and installed the basic software (Alsa for audio, wireless_tools and wpa_supplicant packages for wireless in the Deluxe edition, etc.)
Audio over HDMI
Many ION boards exhibit problems when trying to play sound through HDMI. They usually require a custom ALSA configuration.
Also, please note that audio over HDMI currently only works in an X session (graphical environment). If you are trying to get the sound to work when running on a virtual terminal, it won't work. Please see this post on the Arch Forums.
The deluxe edition comes with a few extra goodies, such as DC power on-board, mini-PCI WiFi, RCA stereo output, on-board Blutooth, and an included IR Remote.
http://ubuntuforums.org/showthread.php?t=1458300 (Archify(tm) from Ubuntu procedures. Maybe create AUR package.)
The Bluetooth chip is an Atheros with a device ID of 0cf3:3002. It uses the ath3k driver which has been included in the kernel since ~2.6.33 and works out of the box with the default Arch kernel.
The wireless chipset is an Atheros AR9285. Template:Command It uses the ath9k driver, which has been included in the default kernel since 2.6.27. In other words, udev should load the driver without problems -- there should be no extra configuration to get wireless working on the ASUS AT3IONT-I.