Erik mentioned this during the podcast earlier, and I thought some of you might find it interesting. TWICE has an article up listing the various audio options that will be available on both HD-DVD and Blu-ray discs and players. All HD-DVD players must include support for two-channel Dolby True HD, 5.1 DTS HD, and 5.1/6.1 Dolby Digital Plus. Blu-ray players are required to support Dolby Digital 5.1, DTS 5.1 and 5.1 PCM.
More information on the HD-DVD audio codecs is available from the DVD Forum, and info on Blu-ray codecs at Blu-ray.com. They also mention what sort of feature upgrades we can expect, at least in respect to audio second-generation HD-DVD players will add features like 7.1 analog connectors and HDMI 1.3 outputs. As much as we talk about MPEG-2 and h.264, are you taking audio options into account with your next purchase?