I'm going to try and break this down from my limited knowledge. Anybody, correct me if I'm wrong, but this is what I believe:
1) Analog (White/Red) connections will not provide DD surround sound
2) Digital Audio Coaxial cables provide full DD sound.
3) Optical Digital provides full DD sound, converting the signal to light to pass through the optic cable then being reconverted.
The best two without a doubt are numbers 2 and 3. Trying to split what sounds better out of 2 and 3 is near on impossible. To me they sound the same, and provide the best audioo.
Therefore, in your case it seems like analog (1) vs digital (3). Without any hesitation if that is the case you want to go for 3 - the Optical digital cable.