I finally figured out how to activate the DTS function and watched Titan AE w/ DTS and compared it to the DD5.1 and DD2.0 and I tell you, the DTS put the DD to shame, it's not even the same generation. I can't imagine why people say there's no difference!

Also, I bought an S-cable instead of using the coaxial, and I can't tell the difference, is there a difference between the optical cable and the coaxial cable for the audio?

I've used both and can't tell the difference.

And yes...in most cases, DTS is far superior to DD 5.1.

According to DTS and DD official web sites, DTS has a 60% increase in data transfer for the sound. However, it has been said that "it's almost impossible to to accurately compare the two formats (DTS usually produces a higher vloume level, causing it to sound better in casual comparisons)." http://www.dvddemystified.com/dvdfaq.html#1.32 I have talked to many people that agree with this. To my ears, DTS sounds better. But, after researching it, I think that could very easily be just the volume it was recorded at, not the actual sound quaility to my ear. However, mathmatically speaking, DTS does have a higher data stream, therefore is should clinically sound better. To the ear, most cannot hear a quality difference, only a volume difference which is not the same.

Also, the S-Video, unless damaged or defective, should be a huge difference in video quaility. Some of this could depend on your TV however.

As far as optical vs coax digital, a million discussions have been had. There is no real audible difference between the two. What is fact is that coax was intended specifically for DD and DTS 5.1 channel sound. Optical was made for a digital signal for recording CDs and MDs (non 5.1 digital signal). An optical cable can, however, carry the 5.1 channels sufficiently. But, words of advice, a long optical cable can greatly impact the performance of the sound. Also, if there is any crease or kink in the optical cable, the sound is hurt. Most people go with the coax cable when possible, but it never hurts to have system that takes both.

Thanks Bose Pro for your very insightful info. I was wondering about these things as well. Now if I could only find a reasonably-priced place to install a DTS ship into my Denon 3600 reciever, I'd be set.