Unobtrusive speaker cables?

I am currently running a 14' double run of Goertz MI2 for biwiring. I like the sound, but the big shiny copper cables dominate the room. I'm looking for something much less noticeable, but of equal or better sound quality. My system, Goldmund/Timbre/Bryston/c-j/Soliloquy, is revealing enough that I need a high quality cable, but preferrably something under $400 used. Any suggestions?