Hi y w. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif
That is a good question. Tables show Ag and Cu exceeding Au in both electrical and thermal conductivities.
I'm wondering whether gold enjoys a better reputation because Ag and Cu will both carry surface corrosion products after prolonged exposure to the atmosphere, and this can degrade their performance in lots of practical applications, whereas Au retains its clean shiny surface because it is significantly more unreactive. This means that gold may be the better choice in the long run, depending on the application.
You would not be the first to ask this question, and I'm sure that there is a good answer somewhere.