Bobby recommends the Cardas Golden Ref. for a lot of reasons. He definitely has some technical specs that he recommends for cables to work best with his design, so you might want to talk to him before buying something. Of course you might prefer the sound of some cables that don't fit his specs, but it's probably a good idea to know why he recommends certain wire for certain uses. These are a few of the specs he told me about: he recommends 2.5-3.0 meter length (with Cardas, and maybe others too), the tweeter leg of a bi-wire should be 15 gauge or smaller (internal or external bi-wire), and he prefers cable using small gauge copper litz wires. He also said that he usually prefers his jumpers over bi-wire (depending on the particular brand of bi-wire).
I have only used 2.5M Cardas Golden Cross (bi-wire) since I got my Merlins and they work very well. I have yet to try the Golden Reference or any other brand. I have tried several different interconnects and my favorites have been Cardas Golden Cross, Coincident, and Luminous Audio Synchestra Signature (with the Luminous being my fave so far). Bobby doesn't recommend silver wire for his speakers, but several people on Audio Asylum are using TG Audio silver wire with the Merlins and say they make a good match. Good luck.