Firewire connection (on e.g. Denon AVRs)

[khewa]

Both NVidia and ATI have announed their intent to add HDMI to their upcoming graphics cards.

Firewire is just a transport protocol, so it could conceivably be used to connect a PC to a receiver if sofware were written that knows the data format to send over the firewire link.

p.s. DACS don't decode audio formats. You would need an external decoder that could decode all of the formats you mention. They currently exist for Dolby Digital and DTS. Rebook CD is PCM and MP3/WMA are lossy compressed versions of PCM, so they work right now. Licensing restrictions are what slow down support for dvd-a (MLP) and SACD (DSD), but sooner or later that will probably happen too.

the current AVRs have combined the decoder and DACs in one box. Licensing restrictions has already been worked out between the relevant companies. If you look at the Pioneer AVR, it supports all the formats (sacd, dvd-audio, dts, dolby).
What we need now is software on the PC side to send the audio data over the firewire link.