Question : What app/codec for DVD playback.

I'm looking for direction to which program to download/purchase for DVD playback with and emphasis on audio output. I'm not focusing on watching movies so much as getting best audio playback of concert-based DVDs. I have a digital (coax) connection going out to my home theater amp.

Given that, it's not clear to me exactly what combination of codec and app support i need to playback DVDs. I'm prepared to pay for this...but i don't want to waste money either.

Answer : What app/codec for DVD playback.

I'd recommend you also look at VLC Media Player:

http://www.videolan.org/vlc/

"VLC media player is a highly portable multimedia player for various audio and video formats (MPEG-1, MPEG-2, MPEG-4, DivX, mp3, ogg, ...) as well as DVDs..."
Hope this helps!