What motherboard do you have? Your integrated audio may already support HD audio for bluray movies.
The problem is only a few sound cards can do hd audio without the media player (ex..cyberlink) downsampling the audio to 48khz/16 bit. This only affects bluray discs.
If you're going to use Logitech speakers for your audio setup, I would stick with the lossy tracks (AC3/DTS) on the bluray discs.
I am trying to figure out the same thing. Can I run the DVI out of my nVidia card for video and losslessly output analog audio directly to my amps and sub? Will the ASUS Xonar cards allow this? Also, Is there any sort of room eq software that is similar to those on some of the receivers now (that take audio snapshots of the room and adjust accordingly? Thanks!