Z-5500 and X-Fi Elite Pro

I have the Logitech Z-5500's and am connecting them to a Creative X-Fi Elite Pro.



What is the best way to connect them? I.e. what cabling will result in the best sound quality? The options are optical, coaxial and 6 channel direct.



Also, is coaxial the same as SPDIF? My I/O console for my sound card has SPDIF I/O ports but not coaxial, though they look exactly the same and I have read things that have lead me to believe they are the same? Can somebody please clarify this for me.



Thanks

Either optical or coaxial would be good. If you're just getting a short cable connector coaxial will do great, but for really long connections optical will be better.