is either one better or are they the same? also, i'm wondering if i should upgrade my multichannel cables, i'm just using standard ones right now. does anyone know a good cable to use that isnt super expensive?
Depends on the equipment, but often the digital (optical or coaxial) interconnect is better for movies. The 5.1 analogue connection is meant to be used for high-resolution audio, SACD or DVD-A).
CD, DVD-A, and DVD movies use the digital output (either coax or optical), SACD uses the analog mulit-channel ouptputs (their PITA copy-protect method). Both acheive the same end result for the different formats exept that you can record from the digital output and not the analog.
For good cable, I use Blue Jeans Cables. Nice quality & a good price. But if what you are using is working you probably don't need to spend more money on cable.