Why Rhodium?

I experimented a few years ago with two power cables with Acrolink 7N copper wire and one with Oyaide gold connectors and the other with Oyaide rhodium connectors (this was going from the wall to a PS Audio Power Plant Premier). The difference in the sound from just the plating was stark. This is why Oyaide has different types, to voice your system, not WAF as suggested above (though your system may have bottlenecks that keep you from hearing the difference well). In that instance I found the rhodium to be slightly more defined, but it also had some glare. My system had plenty of resolution, so I went with gold to smooth it out and add some body.

I would say the choice is totally system dependent, but I would go with gold to inject a bit of warmth. I don't think relative conductivity is the real issue when it comes to sound. I'm currently struggling with which Furutech plugs and connectors to use in my new setup, because the decision is not entirely straight forward.

I will add that Alex at Wywires has told me he believes that the wire used in the cable does make a big difference on whether you hear differences in plating. He says he doesn't hear much difference between the silver plated connector he normally uses and the FI-50 rhodium.