I asked a similar question a while back and was told that "HD-Audio" vs "Standard-Audio" was about as big of a jump in the movie experience as going DVD to HD for picture. I'm loving the HD picture right now, and my HD-DVD "downgrades" the HD audio to 1.5Mbps DTS for me, and movies like Transformers even sound better that way than they do on the regular DVD (I did a basic sound and picture comparison thanks to NetFlix).
Part of me wishes that I would have forked out the $600 for the top end HD-DVD player to get analog audio outs for use with my really nice, but 3 year old (non-HDMI) receiver, but then again, for $98, I'm pretty happy with just the HD picture right now. Maybe when that HD-DVD/Blu-Ray PC drive gets a little cheaper I'll jump on the HTPC bandwagon. I've been wanting to do that for years anyway.
