Digital Cables in Cambridge Audio D500

I have a Cambridge Audio D500 CD player, and I'm considering getting a Cambridge Audio S700 DAC to add to it. I'm looking to get a more airy sound, a little more detail, and better distinction between instruments. What type of digital cable should I get (it has TOSLINK and BNC connectors)? At this level of equipment, do higher quality digital cables make much of a difference? I currently plan to use the lowest level of Transparent Audio's Digital cable. I'm using Transparent Audio MusicLink SuperXL RCA's for the analog connection right now. Any cheap digital cable recomendations (under $250)?

Get the BNC cable which is the same as Coax/RCA. Another choice is Apogee Wyde Eye. I have a 2 meter one I use to use between the Cambridge CD4 and a DAC. It has RCA on the other end, so it can connect to any DAC. It is under $70. There use to be a Cambridge BNC cable at made to go with the S700. You may want to check to see if they still have some ($35).
Gil, I have been very pleased with the Aural Symphonics bnc/bnc digital cable I bought from to use between my Cambridge cd4se & Assemblage 2.7 Platinum dac. They retailed for about $160.00 and are going for $25.00 on sale.